OceanofPDF.

com

Opal

Gypsumdesertrose

Cinnabar Hemetait
 OceanofPDF.com

E Y E W I T N E S S

R O C K &

M I N E R A L

WRITTEN BY

DrRFSYMES

and the staff of the

NaturalHistory Museum,

London

Pytrie

Geoethi
 OceanofPDF.com

REVISED E DITION

DK LONDON

Senior E d i t o r Carron Brown

S e n i o r A r tE d i t o r LynneMoulding

M a n a g i n g E ditor F r a n c e s c aBaines

Managing A r t E d i t o r Philip Let s u

P r o d u c t ion E ditor George Nimmo

P r o d u c t ion C o n t r o l l e r Samantha Cros s

J a c k e t D e s i g n D e v e l o p m ent Ma nager Sophia MTT

Publisher Andrew Mac i n t y re

A s s o c i a t e Publ ishing D i r e c t or Liz Whee l e r

A r t D i r e c t or Karen Sel f

P u b l i s h i n g D i r e c t or Jonathan M e t c a l f

Consultant Cally O l d e r s h a w

DK DELHI

Senior E ditor S h a t a r u p a Chaudhuri

S e n i o r A r tE d i t o r Vikas Chauhan

A r tEditors Sanya Jain, Sifa tFat ima

A s s i s t ant E ditor Sai Pras anna

Senior Pi c t ure Re s e a r c h e r S u r y a SankashSarangi

M a n a g i n g E ditor Kingshuk G h o s h a l

Managing A r t E d i t o r Govind M i t t al

Senior DTP Desi gner Neeraj Bh a t i a

DTP Desi gner Pawan Kumar

J a c k e tD e s i g n e r Juhi Shet h

FIRST E D I T I O N

P r o j e c tE d i t o r JaniceL a c o c k

A r t Editor NevilleGraham

Managing A r t E d i t o r JaneO wen

Special Ph o t o g r a p h y Colin Ke ates(Nat ural H i s t o r y

Museum, London)and An dreas Einsied e l

E d i t o r i a lC o n s u l t a n t s DrRFSy m e s

( N a t u r al H i s to r yMuseum, London
)

and DrWendy K i r k(Unive r s i t yColleg e London

)

This Eyewi t n e s s ® Guidehas be en conceived by

Dorling K i n d e r s l e y Limited andEdi tions G allimard

This edi tion p ublished in2021

F i r s tpublishe dinGreat Bri tain

98 8inby1

Dorling K i n d e r s l e y L i m i t e d

DK, On e Embass y Garden s,8V i a d u c tGardens,

London,
1 SW1 7BW

The aut horised re p r e s e n t a t i veint he EEAis

Dorling K i n d e r s l e y Verlag GmbH. A r nu l f s. t r 24,1

 OceanofPDF.com

Cut

s t n e t n oC

Baryte

desert

rose

Our rocky planet

Rocks and their minerals

10

Rockformation

12

Weaht ering and erosion

14

Rocks on the seashore

16

Igneous rock

18

The properti
loV canic rock

20

Sedimentary rock

22

Limestone

24

Metamorphism

26

Marble

28

The first flint tools

 OceanofPDF.com

ruO t yenkacol pr

Earth is thought to be about 4,600 million

years old. The word geology comes from the

ancient Greekorf Earthandstudy. The many

different types of rocksfound on our planet

hold valuable details about Earth’s long history

,

Crystal habits

so geologists study them and work out the

crystal is known

processes and events that produced them.

as its habit.

EARTH’S STRUCT U R E

Mineral ores

These are the

Crust, 6–70 km

sources ofmost

(4–43 miles)

useful metals.

thick

Caestietri

(tinore)

Solid mantle,

Cutcitrni e, a
about 2,300 km

(1,800 miles)
varietyof

thick

quartz

Moltenouterore,
c

about 2,300 km

Solid inner core,

(1,430 miles) radius

about 1,200 km

Diamondin

(750 miles) radius

km
i betierl

Earthconsists of aore,
c mantle, and crust.

The crust and upper mantleorm

f vastplates

Gemstones
 OceanofPDF.com

liSealtem
i age of

Seashore pebbles

GangesDelta

Theseareformed by the

weathering of larger rocks

Igneous rocks

by wave action.

The most common

types of rocks have

River Ganges

formedfrom

Quartzite

molten magma.

beachpebbles

Rock s and

sediment

flowingnito sea

Getanri

BayfoBengal

loV canic rocks

l oV canic activity produces

a number of diff
erent

types of rocks and lava.

 OceanofPDF.com

k c o Rdnsa

r i eht s l a r en im

Rocksarenaturalaggregatesorcombintaionsofoneormoreminerals.

JamesHutont

Somerockscontainonlyonemineral,butmostconsistofmore.Minerals

(1726–1797), one

oftheo f undersof

areinorganicsolidswithdefinitechemicalcompositionsandanordered

moderngeology

atomicarrangement.Here,twocommonrocks–graniteandbasalt–are

shownwithspecimensofthemajormineralsofwhichtheyareformed.

Quartz

Granite and its

major minerals

Minerals’ siz
e andtexture vary with how a

rockforms. In the coarse-grained rock,

granite, the major minerals are visibleot

the naked eye: quartz; mica; andeldspar

f.

Mica

Feldspar

Mcia
 OceanofPDF.com

Diverse forms

Rock sarenot always hard and resistant – loose sand

and wet clay are consideredto be rocks. The siz

eof

minerals in a rock ranges from millimetres in a fine-

grained volcanicrockthat cooled quicklytoseveral

metres in a rock such as a granitepegmatite

thatcooled slowly underground.

l e Y olwand whiteaclcite

c r y s atlized in cracks

Rocks
ormed
f withinrocks

This sedimentary rock specimen

isaclaystoneseptarian nodule.

Nodules such as this form when

groundwater redistributes

minerals within a rockandforms

a rounded nodule. This nodule

has been taken out of the rock

thatsurrounded it and broken

open to show the yellow and

whitemineralcalciteinside.

Mesotiel

Naturalzeoliteslike

this fine spray of mesolite

crystals on rockform where

volcanic rocks and ash layers

react with groundwater

.

E Y E W I T N E S S
 OceanofPDF.com

k c oR

t am r onof i

Geological processes work in continual cycles,

redistributing chemical elements, minerals,

and rocks. These processes are driven by

Earth’s internalheatand, at its surface,

by the Sun’s energy.

loV canic

activity

When rocks of the crust

Getanri

and upper mantle melt, they

formmagma, which volcanic

activity brings to Earth’s surface

as extrusive igneous ro cks. Basalt

is the most common.

Ropybasaltic

Granite

alvafromHawai

E Y E W I T N E S S

Igneous mountain

SugarLoaf Mountain

situated in Rio de
 OceanofPDF.com

Wehatering

As wind, rain,ice,andheat act on rocks, they

mayleadto chemical changes or cause the

rocksto fragment andorm

f sediments,

such as sand grains, clays, muds, and silt.

Purequartz sand Claysproducedby

formedfromwtehaered weathneirgare crtcial

getanris or sandstones forsofloirmaotin

T H E R O C K C CY L E

Sedimentary

There is no starting point in this cycle, which has been

bandedclaystone

goingonfor millions of years.

fromUganda

l o V canic

activity

a r T nsport

htaW
eernig

Igneous

rocks

Depositoin

Metnlig

Sedimentary

Metamorphci
rocks

rocks

Magma

Desertsandstone

fromStlcaond

Gneiss
 OceanofPDF.com

h t a egnWi re

no i sodnr ea

All rocks at Earth’s surface break down.eathering,

W chemical or

mechanical, breaks them down where they are. Erosion breaks them

down further as they are moved, by the action ofwater

, ice, or the wind.

aW
ethering due

Wind erosion

totemperature

Sediment-laden wind may

The expansion andontraction

c of rock as the

slowly grind away taa rock .

temperature changes causes it to breakup.

W
retaexpanding in the rock as it freez
es can

cause frost-shattering.

Sandstone

madeof sand

acumtedual

200milion

yearsago

in a desert

Monument
, yeall USA
V

Landscapesarechanged by

weatherniganderosion. Wind

hashelped twaeherawaythe

surroundingrock,levainglarge

“buttes”thatol okkeil monuments.

 OceanofPDF.com

Fresh,unaleretd

Chemical

getanri(left)

weathering

Minerals dissolved

by acidic rainwaetrat

the surfacemay be

carried down into the

soil and rock below

.

Alteredminerasl

Getanriis hardbut
, beocmessoft

andcrumblesetfarweathernig.

weatherdgetanri

Secondary

mnierasl

Rockalteredby

tipneacorlggroundweatr

Chemicalchanges

E Y E W I T N E S S

Thesebrgiht-coed
ulr

se“condaryminerasl”were

Parthenon,thens,
A Greece

formedfromdeposits of

Them
il estone
ounda
f tionsandmarble

dissolvedmineralsfrom

columnsofthisancientGreektemplewere

weatherd rocks higherup

.

bce

builtbetween44
7–432 .Chemicalssuch

ascarbondioxideintheaircause. “acdirani”

Thiscanreactwithstonesuchaslimestone

Iceerosion
andcauseweatheringofmonuments.

As a glacier moves, it picks up fragmentsofrock ,

whichforms part of its base. The moving,froz

en

mass causes further erosion of underlying rocks.

Large rock
 OceanofPDF.com

k c o Rnso e rohseahest

Many seashores are backed by cliffs. Coarsematerial

that hasafllen from above is gradually broken up by

the sea, and sortedinto pebbles,

Gradedgrains

gravel, sand, and mud. These

On the beach, these

various sizes are then deposited

pebbles are sorted by

waves and tides. The

separately – ot be recycled as

sand is pure quartz –

different sedimentary rocks. otherminerals were

washed away
.

Micaschist

Skimming stones

The best skimming stones

aredisc-shaped and are

probably sedimentar y

or metamorphic

rocks, as they split

intosheets.

eastSl

Localstones

These pebbles are metamorphic rocks that have been worn

intofltadiscs on the beach where they were collected.

 OceanofPDF.com

Black volcanic sands

Inareasof volcanic activity

,

beach sand may be rich in dark

minerals. The olivine sandomes

c

fromScotland; the magnetite

bearing sand iseneri

from
fe. T

Darkolivine sand Magnetei-bearingsand

Meduimzs-eidc,oarse Small,ine pebbles Finestpebbles

pebbles

Marcasit
e interiorreveals

c r y s atls radia
ting outwards

Found in chalk

Because flint nodules

are hard, they resist

abrasion, and may be

seen on beaches in

chalk areas (right).

WhiteClis, ofUKDover

Marcasite nodule,

split in two
 OceanofPDF.com

suoeng I k co r

These rocks form when magma from deep within Earth’s

crust and upper mantle ocols and solidifies. Intrusive

igneousrocksolidifiesundergorundandsiealretxposed

by erosion. Magma that reaches Earth’ssurfaceand

erupts is called extrusive igneous rock or volcanic rock.

etoBitgraenit Graphicagretni Redgretani

oLng, angular quartz

Black grains are c r y s atls look lik

e

bioe,titaorm
f ancient writing against Redcolouring dueotthe high

ofmiac the larger

, pale-pink proportion ofpotassium

feldspar cry ats ls feldspar in the rock

Granite

An extremely commonintrusive rock,granite consists mainlyofcoarse

grains of quartz, feldspar

, and mica. The grains are large because they

formed as the molten magmaooled

c slowly deep in the Earth. Generally

mottled,granite varies from greyotred acordingto thedifferent

 OceanofPDF.com

Phenocry st

oef ldspar

Feldspar porphyry

Porphyries are rocks that

contain large crystals called

“phenocrysts” within a medium-

grainedrock. This particular

sample containsfeldspar

crystals andomes
c fromWales.

Basalt

Formedfromsodilfiedalva,

basatslithemostcommon

extruvseirock.Itsisimalirni

compoostigabbr
nt obutfni er

graniedW
. henthealvacoosl,

timaysopm
tniltan-ysided

coulmnsa,seenaStHsenla’

NeedleandNorthernrIealnd’s

GainstC’ au.seway

Green olivine Dark

 OceanofPDF.com

l o c Vi nac

Rocksformed by volcanic activity can be divided into

pyroclastic rocks and lavas. The first areformed from either

solid rock fragments or “bombs” of lava that solidify as they fly

through the. Lavas

air may be thick, sticky
, and flow very slowly
.

More fluid,afst-flowing lavas spread out over vast areas.

Pyroclastic rocks

Pyroclastic rocksconsistofrock and lava pieces

thatwereblown apart by exploding gases.

Ejectionof avl from

dEelf,cIeland,1973

loV canic bombs are

shaped while they fly

through the air

l o V canicbombs

Intrusion

Whenblobs ofalvaarethrown outfoa

bearciofm
r ed

voclanosome
, solidif yin theairand land

withina vent

onthegroundas hard“b.ombs”
Thesetwo

specimensare shapedkeil rugbyo f otbalsl,

asthey spunni, the

butaibombs
r may be

sphercialor riegualr inappe.arnc

 OceanofPDF.com

Viscouslavas

These sticky lavas may erupt, or solidify

in the volcano’s vent, trap gases, and

eruptexplosively, producing pyroclastic

rocks, volcanic bombs, and ash.

ce

seV uvius, 79

This famous eruption produceda nuée

ardente -moving cloud

,afast of magma

and ash, and destroyed theoman

R town

ofPompeii.

Aphtheail

Floatingrocks

Pumiceissolidified

alvath.
roBecausethe

roothntcanisbubbles

ogas, theock
r is

pepperedwith holes.

Pumiceisthe onlyock
r

that.fol atsniwat
er

Rocks from gases

Inactive volcanoes are called “dormant”

,

Grainsof rhyoleit

but escaping volcanic gases mayform

are very small

minerals, such as yellow sulphur and

blue aphthitalite.

E Y E W I T N E S S

Santorini

The Aegean island o Thera(nowcalled

Santorini)wasdevastat
edbyavolcanic
 OceanofPDF.com

y ratnemi deS k co r

Weaht ered and eroded rocks break intosmaller

piecesof rock and minerals. This sediment may

o(ften seawater) evapoaret

be transported ot a new siteoften

( alake, river
,

and leave deposits of minerals.

or sea) and deposited in layers that become

Examples include halite and

gypsum.We get table salt from

buried and compacted. Cementedotgether

,

halite(rock salt). Gypsum, used

inplasterofParis, is cal
the particles formnew, sedimentary rocks.

alabaster in its massive form.

Hole-filled, irregular-

shaped rock

Clay

Formed of microscopically

fine grains, clayfeels

sticky when wet.

When it is compacted

and all the water is

ceorf d out, it forms

hard rocks called

sometm
i esfoundinm
il estoneacves.
mudstoneor shale.
 OceanofPDF.com

Rock builder s

Foraminera
if are microscopic marine organisms that

secrete lime. When they die, the shellsallf ot the

oceanfloor where they eventuallybecome chalk

andmaybecomecementedto formlimestone.

Shelly
Fnilt

Chalk

m
il estone
Aformof cislai keil(quartz),

lumpsof nilt aer etfonfound

nim
il estones,especialy chalk.

Theyare gery orblack, but

maybeoc veredni awhie,t

powdkeilr-mat
erial.Like

obsidian,when nilt isbroken,

ithas aonchoi
“c dal”fracture.

Gastropod

m
il estone

Remainsof

Oteoil

gastropod shell

Lm
i estones

Manysedimentaryocks
r consistof theemai
r nsof

organisms.In theseshellyand gastropodmilestones,

theremains ofanimalsare celayrl visbiel intherock.

Chalkis alsoam
il estonfeo,rmedfrom theotesklens

oftniy seaanimalstoosmallot see withthe naekd

eye.Ool
e,anot
ti herm
il one,
estorms
f ni the seaas

etcialbuilds uparoundgrainsof sand. As theyare

roeldtoand froby waves, thegrani sbec

ome
. alrger

The Grand Canyon, US A , is a UNESCOorld

W Heritage Site, carved

out over millions of years by the Colorado River as it weathered and

eroded the rocks. The sides of the canyon are mainly layers of softer

sedimentary rocks, including limestone,sandstone,mudstone, and

shale, above a harder

, older basement of mainly metamorphic rock.
 OceanofPDF.com

eno t s emi L

Limestone caves, lined with dripping stalactites

and giant stalagmites, areformed when slightly

acidic rainwaterchanges the limestone’s

chemistry
. This makes it possibleorf the

torock dissolve in water and

be washed away
.

f uTa

A type of rock known as a

precipitate,tufaforms when

lime is deposited fromwater

ontoarocksurfaceinareas

oflowrainfall.

Coral-like

structure

Plan de Sales,

France

Limestone pavements

offlatblocks occur

whereweathering

leaves no insoluble

residueto make soil.

LIMESTO N E L A N D S C A P E S
 OceanofPDF.com

o T psectionattachedto

theroof ofthevac e

Stalactites

Stalactiest areformed in caves by

groundwatercontaining dissolved

lime dripping from the roof and

leaving a deposit as it evaporates.

Growingdownwardsafew millimetres

each year – shown in annual growth rings –

they may slowly reach many metres in length.

Stalactiest ma
ytake

hundredsof years to form

E Y E W I T N E S S

Ease Gill Caves,

England

yloar nI1946TBl,i

andGeogreConres

eocsvrdithefrist

ecnartneotges
htaerl t

cavesytemnithe

UK. Torefhestonife

etiactraoltsfmsthe

mostspectacualrpartof

shctoim
xcavespym
elt.s

Pamukkaleur
Fallks,eyT

Beautiful travertine terraces are

formed from the precipitationof

calcite fromhot springs in limestone

ar vertine
areas.T is quarried as a

decortaive building stone.

 OceanofPDF.com

ms i hp r oma t eM

Metamorphic rocks are igneous or sedimentary rocks altered

by heat and/
o r pressure. Such conditionscanoccur during the

mountain-building process, as buried rocks are subjectedto high

temperatures and squeezedorfolded,creating new minerals.

oexPryne-bearing

marbel

Nodular

greymarbel

Sachoiardal

Eclogite

marbel

Produced under very high

pressure, eclogite is extremely

dense and is thought toform in

Spoetdsleat

the mantle – far deeper than most

otherrocks. It containspyroxene

and small, red crystals of garnet.

 OceanofPDF.com

Slate

During mountain

building, shale was

squeezed so hard that its

flaky micas crystallized

atrightanglesto the

pressure. The resultant

rock–slaet– splits easily

intothin sheets.

White

muscovitemica

Ganre-t

mue-
scotvi

Green chlorite

chlortieschist

mineral

c r y s atlsof kyanite

Pink granitic rock

Dark

C r y s atlsof a

green variety

Migmatite

pofyroxene

Underintense heat, parts of rocks may startto

meltandflow,creating swirling patterns. This

is very often shown in migmatites. They arenot

composed of one rock but a mixtureofadark

host rock with lighter-coloured granitic rock.

This sample is from the Scottish Highlands.

 OceanofPDF.com

Medici Madonna

e lbraM Italian sculpt

or Michelangelo sculpted

thisstatue fromCarrara marble in

the16thcentury. He personally

Marble is a metamorphosed limestone, but

checked the marbleotbe used

its name is often used in the stone industry

fromCarrara and Pietrasanta,

and chose particular stonesfor

fora variety of otherrocks. All are valuedorf

their shape and size.

their attractive rangeoftextures and colours,

and because they are easily cut and polished.

The world’s most famous marble comes

from the Carrara quarry

uscany,intIayl. T

Greekconnection

It was the local stoneorf Michelangelo.

Originally from the Greek

Island of Euboea,

streaked Cipollino

Italian speciality

marble(above)is

Grey Bardilla marble (left)

 OceanofPDF.com

u T scan

stones

The distinctive

textureof the Italian

decortaivestone,Breccia

Violetto,was the reasonorf its use

intheParis Opera House in 18

75.

South

African swirls

Polished travertine

has beautiful swirling

patterns. This piece is from

CapeProvince, Southfrica.
A

a T j Mahal, India

Built by around 20,000 artisans,

this monument is made of

ivory–white marble. Swiss origins

Thelimestonebreccia

known as Macchia

vecchiais quarried in

Mendrisio, Switz
erland.

Detaiolf
 OceanofPDF.com

t s r ei hfT t n li olo tfs

Because flint splits in any direction, fracturesot a

sharp edge, and is fairly

spread,wide
it was used in

prehistoric times to make early tools and weapons.

TOOLS FROM FLINT

Flinttools were shaped by striking a flint nodule

or fragment with anotherone,

st or hitting it

againstarockto breakoff flakesof flint.

Stone-on-stone

Striking the flint

Crude withastone ecrat d

earyl
sharp, jagged edges.

chopper

Rough

cutting

Large,sharpened
edge

Handaxes

handaxe

Palaeolithic handaxes were used to smash

animal bones, skin hunted animals, and cut

wood and plants. The well-developed, dark

 OceanofPDF.com

Nnithc-enturyobsidian

axefromMocexi

and dagger

Mesolithic

The shape of this

adez

EarlyBronze Ageaxe,

Antler

found in the River

sleeve

Thames in the UK,

imported. Polished

withcare, it was

clearly an object of

Obsidian

value. So,too,was

Like flint, obsidian was used in earlyools

t

the Early Bronz

e Age

because it fractures with sharp edges.

ger (2300–
flint dag

Spearheadwith obsidian

bladefrom theAdmiratly

Islands,oaP puaNew Guniea

Cutting edge

offltin

Adzefromthe Mesoltihci

bce

peroid(100, 00–4000 )

Flint

mounted

directly

onto

handle

Sickle

Flint sickles show crops were cultivated. The

long, slightly curved blade was swung from

Reproduction

sidetoside to harvest crops. A “gloss” on their

wooden

cutting edge shows repea

ing.tedThis
harvest

handle

bce

i N lithi (4000 2300

 OceanofPDF.com

k c oRs s l oos ta

ologists
Archaehaveound
f lotsofrocks that have been

shaped by people from many different cultures around

the world. Some were used as weapons or status

symbols, others as afrming or household ot ols.

Braziailnstoneeax

Wedgeostop

thestonemoving

Bored

quartzite pebble

Neoltihciaxeshowing a

highlypolished esuafrc

Stoneaxes

Thesestoneaxesdate

backtoNeolithic Britain

bce

(4000–2300 ).

Highly polished and

tougher than flaked

flint axes, theywere

traded over long

Neoltihciaxemade of

distances – the source

doirtiean
, igneous rock

rocks werearf from

the places where the

axeswereound.
f

Digging stick

During the Mesolithic

and Neolithic periods

Neoltihciaxemade of

bce

rhyoltictu,a vocalnicrock
(10,000–2300
 OceanofPDF.com

Marble make-

up palette

Romans used powdered

lead and chalk to whiten

skin; red ochre totint

lips and cheeks; and soot

EngarvedVikingo f rge

todarken eyebrows.

stonemade ofsoap stone

Small amounts were put

andusedinmeta-wl orknig

onastonepalette or in a

Whetstones stonebowland mixed

Abird-shaped with, tree

waterresin
Bronzeimplements

mortarcarvedby

(gum), or egg white

ened
were
bysharp

HaidaIndians

tomake aoloured
c
rubbing the blunt

paint or paste.
edge against a

whetstone. These

two are Bronz

e Age

bce

(2300–700 )

and were worn

onacord.

Roman rotary quern

A quern was used for grinding corn

between two stones. The upper

one was held in place by a

spindle and was rotatedby

a handle. Grain was fed

through the hole in the

upperstone, and the

rotary motionorcfed

it between the two

grinding surfaces.
 OceanofPDF.com

s tnemg i P

For body and rock art, early humans

crushed local rocks and mixed the

powders with animal fatsto produce

a range of pigments. Over the

Green

aycl

centuries, as trading routesgrwe, Powdeerd

greenclay

artists had new colours to work with.

Ochrepaint

Whitechalk

Shades of white

The first white pigment

was ch

clay)instead.

Powderedchalk

Colour variation in a mineral

Many minerals areuniformly coloured, but

some come in a rangeofolours.

c For

example,ourmaline
t above
( ) may occuras
 OceanofPDF.com

Powdeerd

hemetait

Iron red

The earthy variet y

ofhematite,anironore,

produces a rich reddish-brown

Redpanit

pigment.
er Vy finely powdered, it

was also used as make-upfor skin.

Powdeerd

orpm
i ent

Powdeerd

malchtei

Bright gold

Medieval artists used

orpiment, an arsenic

Brilliant green

compound,otmake many

Bronze-Age Egyptfirst

Malachite
colours andtoimitategold.

used malachite,acopper

Greenpaint

compound,orf green.

Ultramarnie
 OceanofPDF.com

gn i d l i uB

Most of the great monuments of the past survive because

they were made from tough, natural stone.Generally

, local

stone was used, but sometimes stone was transported

Quarryingni the eayrl 19thentur

cy

long distances and even across seasfor building projects.

wasstil donealmostentrielyby

manual
. labour

Nummulitic limestone

Formed 40 million years ago,

nummuliteis aamous
f

limestonemade up of

fossilscalledforaminif
era.

Thepyramidsat Giza, Egt,yp

weremade ofolcalnummultie

m
il estone.

Foraminera
if

Portland stone
fossils

etAfr the GreatFire of London in 1666,

StPaul’sCathedral was rebuilt with this

English limestone. The marks are made

by “tooling”
, adecorativeechnique.
t

Christian mosaic

Small fragments of local

stoneswereoften used

l eWsheslat

formosaic floors.
 OceanofPDF.com

NotreDame,Paris

This famous cathedral in Pantile

Paris,France, was built

from local limestone from

the Stacques
J region of the

city, between 1163 and 1250.

Thecatacombs inaris
P are

old quarries.

Sandstones

raV ious coloured sandstonesmake

excelent building stones, as seen in

nIterlocking

rooftile
many fine Mogul monuments in India.

Materials

Many modern buildings are

made of bricks, tiles,ement,

c

concrete,and glass (from silica sand).

Oolitic

230m
-oilniy-ear-oldsandstone

limestone

This building stone

formedsome 160

Skyscarpers

million years ago.

orkskyscrapers
NewY

aremade ofegrtan,i

sandstone,and

Redsandstonerom

manufactuerd

tocSlandused ot give

m
retials.

acoveringyerla

tobuidl nigs
 OceanofPDF.com

y r oethsT

a of col

The coal we burn is millions of years

old. In the swampy forests of Asia,

Europe, and North America, rotting

leaves, seeds, and dead wood became

buried. Overlying sediments squeezed

thewater out and compressed the

plant matter intopeat and then coal,

layer upon layer

. As pressure and heat

gerw,other types of coals wereformed.

Fossilized wood

Jetishard, black, but very light and is

derived from driftwood laid

down in the sea.

Polished and

carved, oftenorf

jewellery
, it has

been used since

theBronze Age.

Coal as
 OceanofPDF.com

faeL

The beginning

ofthestor y

In areas with thick layers of

vegetation and poor drainage,

such as swamps or bogs, dead

plantslogged.
becomewater

Stakl

Theystarttorot, butcannot

Seed case

decaycomple.tely

The peat layer

Peatis amorecompactform of

the surfacelayerofrotting plants.

Someroots and seed cases are

still visible. Newlyormed

f peatcan

be cut, dried, and burnt as a fuel.

Browncoal

Naturallycompressedpeat

formscrumbly, brownlignite that

stil containsrecognizable plant

remains. Undried peat is 90 per

centwater; lignite is 50 per cent.

“Black gold”

Under pressure,lignite isconvertedinto

bituminous or household coal. Hard and brittle,

it has a very high carbonontent.

c A charcoal-like

powdery substancemakes theoal

c dirty tohandle.
 OceanofPDF.com

s l i s soF

Fossils are the evidence of past life preserved in

the rocks of Earth’s crust. When an animal or plant

is buried in sediment, usually the soft parts rotaway,

but the hardest parts remain – most fossils consist of

the bones or shells of animals, or the leaves or woody

parts of plants. In some marineossils,

f shells may be

replaced by other minerals, or an impression of the

insides or outsides may be preserved. Fossilsarefound

in sedimentary rocks, especially limestones and shales.

Muddy

rock

Fossil

Leafimprint

eafl

About 40 million years old,

thisfossilleafaf( r left) is

similar to the modern

beech.leaf

Beech

eafl

Impression

oflefa
 OceanofPDF.com

Buried bones

Ancient ancestors

Dinosaur bones buried in

Ammonites were sea creaturesthathadhard,

sediments such as mud may

coiled shells, and are now extinct. Because

slowly turn intorock. The fossil

ammonites changed ar pidly and lived in many

bones may be replaced by

areasofthe world, they can be usedotdetermine

minerals such as calciteand silica.

therelative ages of the rocks in which they occur

.

The nearest modern equivalentto the ammonite

is the nautilus.

Fossil hunting

The abundance of

fossils on seashores

made collecting a

popular pastime in

the 19th century.

Garden

snaisl
 OceanofPDF.com

e c apS s kco r

Greytinerior

Thousands of meteorites that weigh

consisting

mainlyof

over 450 g (1 lb) fallot Earth every year;

the minerals

olivine and

most land in the sea or on deserts. Only

oepxryne

afewarerecovered annually
. As they

enter Earth’satmosphere, their

surfaces may melt and form a crust,

protecting the stony or metallicinterior

.

Pasamontefireball

Photographed in New

Mexcio, U S A , this fireball

felltoEarth in March 1933.

Meteoriest are named after

the places wheretheyfall –

Dark, glassy
this one in Pasamonte.

fusion crust

The fireball broke up in the

formed during

atmosphere,leadingto

passage

the fall ofdoz

ens of

through Earth’s

meteoriticstones. atmosphere

Ironmeteorite

The Canon Diablo meteorite is an ironmeteoritethatfell

toEarth about 20,000 years ago in Arizona, USA. Iron

meteesortiaremadeofironandnicelkfromthecore

oftheasteroid. The Earth’score is also made of

iron and nickel.

 OceanofPDF.com

Halley’s

Comet

W
reta-bearing

meteoriest may

havecomefrom

comets, such as

Halley’s – here

depicted in the

11th-century

Bayeux tapestry.

ASTEROID STRU C T U R E

Manymeteoritesome
c fromthecollision

ofasteroidsthat orbit the Sun. The type of

meteorietthat lands on Earth depends on

which part of the ast

eroid reaches us: iron

meteories,
t lik
e Canon Diablo,are fromthecore

oftheasteroid;stony-ironmeteories,
t lik
e Thiel

Mountains,are from theore-mantl

c e;andstony

meteories,
t lik
e B a r well, are from the crust.

Crust

Core -

mantle

Mantle

Meteoriet

containsdoz
ens

ofamino acids,

Core

manyfowhich are

notfound on Earth

Rocks from the Moon and Mars

The Nakhla stonefell in Egypt in

Fivemeteoritesound
f inAntarctica are knownothave
 OceanofPDF.com

s l a r en iM

Eight elements make up nearly 99 per cent of

Earth’s crust,combining toorm

f minerals that

formrocks. Certain mineral groups are typical

ofcertain rocks. Silica minerals predominate in

most common, mostly igneous, rocks.

Minerals in granitic rocks

Feldspars, the mostommon

c minerals, plus quartz,

micas, and amphibolesorm

f granitic and dioritic rocks.

Group

Single

ofblack

hornblende

prismatic

crystal

c r y s atls

with

calcite

Colourelss

quartzock
(r

crystal)

Hornblende,an

amphbioelc,ommon

Silvery
, radiating,

inigneous andsome

needle-like c r y stals

metamorphicrocks
 OceanofPDF.com

Basic rocks

The minerals shown here are all

found in basic rocks like basalts

and gabbros.

Pinkcrystaslofanorthiet

plagioclasefeldspar

Green

olivine

c r y s atls

Whitecrystalsofalbtie

plagioclasefeldspar

Anorthite

wtihcacltie

Calcite

Albite

Nepheline,a

Thinsectionof a basalt

fedlsthoi
pa d,

Olivinebasaltervesalbrgi htyl

wtihcacltie

couelrdolivine, brown-

yelolwpyrxeneo, andminute

Plagioclase

greyplagioclaseefldspars.

fedlspars

Commonin

igneousrocks,

loV canic

theseminerasl

rock

)oabno(vectani

sodiumand cacluim.

Fedlspathoids

Thesemineraslhave lesssilicathan Crystalof elucte,i

edflsparsand typicalylformin voclanci alvas. afedlspathodi

 OceanofPDF.com

s l atsyrC

The word crystalcomes from the Greek word

kryos , meaning icy cold – rock crystal,aform of

quartz, was once thought to be deep-frozen ice.

In fact, a crystal is a solid, with a regular internal

structure. Dueot the arrangement of its atoms, it

mayform smooth external surfaces calledfaces.

Many crystalshavecommercial uses, and some

are cut as gemstones.

C r y s atls orient
ed

in random gro
w th

directions

Lightreflecting on

Well-developed
the cry ats lfac
e

afces

Planeof

niter section
 OceanofPDF.com

What’sthe?angle

Crystal symmetry

As theanglebetween

Crystals can be grouped into seven sy stemsaccordingto

coerspondingesfac

their symmetry
, which is shown in certain regulareatur
f es

ofa particularmineral

of the crystal.Forexample,for every facethere may be

sialways the same,

another on the oppositeside of the crystal that is parallel

scientsitsmeasurethe

to it and similar in shape and size. But in most mineral anglewith acontact

gonoimeterto help

specimens it can be difficult to determine the symmetry

identify theminera.l

because crystalline rocks may notalways show individual

crystals with well-developed faces.

r T iclinic

Cubci

Thissyst
em’scrystals dsipaly the

Metacilporms
yrtief cube-

leastsymmetr
, asyshownby this

shapedcrystalsbut
, other

wedge-shapedaxnitiecrystal.

cubicmineraol f rmsinclude

octahedraandtaerhedar.

One variety

Crystals inthissystemexhibit

has silky lustre

thehighest symmet
. ry

Rhombohedrtraigl(onal)

Smalelrsecondarycrystals have

grownon thissidertiecrystal.

Quartz,tourmanilec,orundum,and

cacltiebelongtothe samesyst
em.

Monocnilci

Hexagonal
 OceanofPDF.com

l atsyrC htworg

No two crystalsareexactly alike because

the conditions in which they develop vary

.

They range frommicroscopic to several

metres long. The shape of a crystal or

Coral-like

aggregate of cry stalsconstituteits “habit”

.

Fine cry ats l

Radiating needles
“needles”

Slender
, elongated crystals

aresaidto havean“acicular”

(needle-like
) habit. In this

scolecietspecimen, grey

acicular crystalsradiaet

fromthecentre.

Sparkling aggregate

Hematite occurs in several

habits. When itorms

f shiny
,

reflective cry stals, it

Short, hexagonal

is said to have a

terminalacef

“specular” habit,

ateachend

as in this

aggregate.
 OceanofPDF.com

Sandy

Dualform

cubes

Pyrite crystalsorm
f as cubes and as

crystals called pentagonal dodecahedra,

Salt lake,Cyprus

with 12 faces (“dodeca” means 12), each This shallow salt lake

ontheMediterranean
the shape of a pentagon (“penta
” means

islandofCyprus dries

five).Grooves called “striations” may

upintheheat of the Sun,

formonthefaces.

leaving a crust of salt

crystals behind.epe
Rated

replenishment by salty

Stepped crystals

waterand drying out by

This halitecontains

evaporation builds up

numerous sand grains.

layersof salt.

It grew along prefered

axes,orming
f a stack of

cubic crystalsinsteps.

Parallel lines

During crystal growth a series of crystals

of the same type may develop growing in

the same direction. This calcite

Metaciletpyir
aggregate shows a number of

tapering pale pink and

grey crystalsinperfect

Double decker parallel orientation.

Chalcopyriteand

sphalerite crystals

have similar

structures. Here,

tarnished, brassy

chalcopyrite crystals

have grown in parallel

o T pof

on brownish-black

glsitening pink

sphalerite crystals. calcite c r y stal

group

Baseof grey

Sphaleritec r y ats ls

calcite c r y stal

Chalcyrit
ope

group

c r y s atls
 OceanofPDF.com

se iet hreppr
To

fo s l a r en im

Most minerals have a regular crystal structure and a

definitechemicalcomposition. These determine the chemical

and physical properties that are characteristicorf each mineral

and help geologists to identify it and see how it wasormed.

f

Modelof

garpethistructure

Structure

Some
cally chemi

identical minerals exist

Carbonom
at

in more than one

form.Forexample, the

Carbon

element carbonorms
f

omta

two minerals: diamond

andgraphite.

Garpethi

specimen

Garpethi

Inthis hexagonal mnieroal f rmedunder higehmtpteuraes,

eachcarbonota m is closelynilkedtothree others in thesame

. Buitl ayleup
r ofwidely spacedalyersonly weakyl bonded

, graeptohgtiestiherverysoft (1-2onthe Mohs hardnes e)csal.

Cleavage

Thin lines

When crystals break, showcleavage

 OceanofPDF.com

Hardness

THE MOHS SCALE

The bonds holding atoms

togetherdictate a mineral’s

The scale createdby Friedrich Mohs classifies minerals

hardness.In1812,mineralogist

based on their hardness (scratchability). The int

ervals

Friedrich Mohs devised a scale

between the minerals in Mohs scale are not equal.

of hardness that is still in use

Diamond (10) is about 40 times harder than talc (1).

today
. He chose ten minerals

Thedifferencein hardness betweenorundum

c (9)

as standards andarnked them

and diamond (10) is more than the diff

erenc
e

so that any mineral on the

between talc (1) andorundum

c (9).

scale would scratchonly

those below it.

1 2 3 4 5 6

a T cl Gypsum Cacteli Fuloteri Apetait Orthoclase Quartz

Magnetism Optical

Only two common The optical effect as light passes through

minerals, magnetite a mineral is dueot light’sinteraction with

and pyrrhotite(both atomsin the

ironcompounds), are structure.

strongly magnetic.

Magnetite lodestones

were used as an early

formofcompass.

Clusters of

iron filings
 OceanofPDF.com

s eno t smeG

Gemstones are minerals ofgreat

Diamond

Diamond is named from the Greek

beauty
, rarity
, and resilience.

word adamas (“unconquerable”).

Light reflectsandrefracts with It is the hardest mineral of all,

and famedorf its lasting fiery

the mineralsot producethe

brilliance. The quality of a gem

diamond is measured by the

intense colours of gems, such

four Cs: its colour

, clarity
, cut,

as ruby and emerald, and the

andcarat weight.

“fire”of diamond. Colour

, fire,

Diamond cry ats l

and lustre are revealed by

skilled cutting and polishing

foruse in jewellery
. Gems are

usually weighed by the carat,

equal to one-fifth of a gram.

Kimberlite

e r T asuresinvelagr

Un18lti70diamond crystalsand

fragmentsacmefrom rvier vagrels,

mostlyin India orBraziThen

l. South

isrfA’ac diamond-rcih km
i betirl

madeit theeladin.gsupplei r

Coloursofdiamonds

Diamondsrange fromolocurless

throughyelolw andbrowntopink,

green,blue, andavery
able,rarered. T

rose,andbrailnt cuts dsipaly their QueenMary

, wasgivento
 OceanofPDF.com

Sapphirecrystal

Corundum

Rubytendstoofrmin atl

Ruby and sapphire are varieties

crystals, whiel sapphire

of the mineralorundum,
c which

tends
otbe barre-lshaped

is colourless when pure. Tiny

orpyramidal,

quantities of chromium make

oftenwith

ruby red. Iron and titanium zonesfoblue

toyeol w

give the blues, yellows,

. coulr

and greens of sapphire.

Starsapphrie

oSnteswithine,needle-

kilecrystals oeritendta

inthree directoins can

becut asstarrubies or

TheEdwardesRuby

starsapphreis.

Thiisptecexonalcrystalweighs

261 tas.racIt is almostcertainly

fromthe famous gemdeposits

ofMogok,Myanmar(Burma).

Cutruby

Gemsources

Austraailsuppleis themostblue andyelowsapphires.

Rubiesare minedniMyanmar
, Thaialnd, andcentral Blue Colourelss

irfAca.Sri Lanka sifamousforblue andpinksapphreis. sapphire sapphire

Whiteopal

Opal

Opal probably gets its name from India,

from the Sanskrit word upala

(“preciousstone”).oman
R

jewellery used opals from

theCzechRepublic. In the

1500s, opal came from

CentralAmerica.After
 OceanofPDF.com

Lapis lazuli

This blue gem consists

mainly of lazuriteand

a r oecviet D
sodaliteminerals with

whitecalcite and

specks of brassy-

colouredpyrite.

s e no t s

u T rquoise, agate,lapis lazuli, and jade are

all gems made up of many crystals. They

are valued mainlyorf their colour

, evenly

distributed as in turquoise, or patterned

as in an agate cameo.Agate and jade are

also tough, idealfor fine carving.

i eV nof

turquoise

Lapiscrftas

Longusedo f rbeads and

carvings,al pishas beenknown

formorethan 60,00 yearsand

isnamed from thePersian

wodr Lahzward (“bul e”).

 OceanofPDF.com

etAga

Chalcedony

Bandedagat
esorm
f

Carnelian, onyx,
prase,chryso

nicavitiesin voclanci

and agateare allforms of

rocks.Uruguayand

chalcedony. Purechalcedony

Braziare
l the

is translucent greyorwhite
manisources.

andconsists of thin layers of

tiny quartz fibres. Impurities

createthe patterns in agae.t

C r y s atls

Polisheded
slic eagta

Anceinvotefuatri

Mcoriscopiccrystasl

Apple-greenchrysoprase

ofm
redin bandsas hosit,lica-

hasbeen usedni

richsolutionsetliredthrough

jewellerysince

caviteisinporous rocks.

Repo-rmantimes,

oftenascameos

orni taglois.

Cameoportrati

Thisbloodstone

Chrysoprase

showsoman
aR

cabochon

. emperor

Mughaldagger

Jade

Mughalcrftsmen
a

Named from the Spanish

carvedpalegreen and

piedra de hijada usedto

greynephr
etionit

describe the green stone

daggerhandles, bowls,

carved by the Indians in

andej wel, el ry often

CentralAmerica, jade inlaidwith rubies and

 OceanofPDF.com

rehtO smeg

As well as well-known gemstones such as

diamond, ruby
, sapphire, emerald, and opal,

many other minerals have been used for human

adornment. These are just some of the stones

frequently seen in jewellery

, but the full range

oflustre, fire, andoclour isextensive.

Smallruby

Blue
Spinel

spinel

Redspinels resemble

rubies and were once

called balas rubies,

after Balascia, now

Badakhshan in

hgfA anistan. There is

Pinkspinel
also a range of pink,

lilac, blue, and bluish-

Mauve

greenstones.

spinel

p o T az

Occurring chiefly in granites and pegmatites,

some gem-quality topaz crystals are very

large, weighing many kilograms. The largest

stonesarecolourless or pale blue, but the most

valuable are golden-yellow imperial

topazor pink topaz.

 OceanofPDF.com

Garnet E Y E W I

Garnet is a groupnamefor

Byzantine relic
a diverse set of gems that

ManyByzantine artefactswere

includes almandine and

made of gold and decoredta

pyrope(red and purplish-red),

withpreciousstones.Crafted

spessartine (orange-red),

Grossular

inConstantinople, the Limburg

grossular(orange,green,orcolourless),

garnets

Staurothekeisaontai
c ner

anddemantoid(green). Fine green

forholy remains. Featuring

demantoid garnet has a bright emerald

Roes -cut

nine enamel panels, it depicts

stone

colour and is therarest and most

angels surrounding Christ on

expensive of the garnets.

athrone,Virgin Mary
, and

StJohnthe Baptist.

Greekdiadem

Thissection ofanHellenistic

Garnetearrings

Named from

diademdat
esfromthe 2nd

eRso-cutstones

bce forgolden coloured. Zircon occurs in

centuyr ,and isni laidwith

maketractive

manycolours, including reddish brown,

garnets.Its design sicommonto

jewellerywhenset

manyGreek atefractsfothattime.
golden yellow
, yelol w, green, blue, pink,

ingold, asshown

and colourless. Brownziron

c can be

bythese 18th-

heat-treatedandirradiaed
t otcolourless

centuyrearrings.

orbluestones popular in jewellery

.

Almandine Hesontie Pyrope

Pink Green

corniz corniz

Demantodi

Demantodigarnets

Peridot

This is the transparent gem variety of olivine.

The proportion of iron in the mineral

determines the shade of colour

. The

Amethyst

more valuable golden-green

Purple amethyst is a variety of

and deep-green stones

quartz. Colourless, transparent

contain less iron than those

 OceanofPDF.com

e rO s l a r en im

Mined, quarried, or dredged from lakes and rivers, ore

minerals are crushed and separated, then refined and

smeltedf(used and melted)to produce metal. Copper

bce bce

was in use well before 5000 . Around 3000 , tin was

added to make a harder metal, bronze.Iron was even harder

bce

and was widespread by 500 .

Bauxite–
Colourfulcopper

aluminiumore

Brassy
, yellow chalcopyriteand

bluish-purple bornite are

ommon
c opper
c ores.

Because it is a good

conduct
, r o copper is used in

the electricity industry

, and

because it is malleableeasy
( to

shape and roll), it is goodorf

household water pipes. It is also

Aluminium used in alloys with zinc (brass)

Lightweight
kitchen
oil f
and with tin (bronz
e.)

aluminium

Aluminium is lightweight, a

goodconductorofelectricity,

not easilyorroded,
c and used

in power lines and saucepans.

o T ugh iron

Hematite is the most

Stacksof
 OceanofPDF.com

Sphalertie–

Durable nickel

zincore

Nickelomes
c from deposits in

large,layered gabbroic intrusions

and from depositsormed

f by the

weatheringof basaltic igneous

Gvalzneid rocks. Nickelineoccurs in small

nail

amounts in silver and uranium

deposits where nickel is a

by-product. Nickel is used

incorrosion-resistantalloys,

such as stainless steel and in

empera
t ture,high-
high-

strength alloys suitablefor

aircraft and jet engines.

Nickelalolybattery

Black jack zinc

Cinnabar–

Sphalerite or “black jack”

, as it was known by

mercuryore

miners, is the most important zinc ore and is

foundin deposits in volcanic and sedimenta ry

rocks. Zinc is used in galvanizing –oating

c sheet

steelwith a thin layer of zincto prevent

it from rusting.

Leadsolder

Soft and shiny lead

Galena, the main lead ore, is

workedchiefly from deposits in

limestones. Lead is the densest

andsoftestcommon metal, with

a high resistanceotcorrosion,

but it is not very strong. It is

usedinstorage

batteries, petrol,

engineering and

plumbing,

and with tin

 OceanofPDF.com

s l a t em

suo i ce rP

Gold and silver were among the first metals discovered.

laVuedfor beauty and rarity, they – and platinum in the last

100 years – are used in coins to prove wealth, buy, and sell,

and in jewellery and other objects.

Platinum

Popular in jewellery, platinum is also used

in oil refining and in reducing pollution

fromcarexhausts.

Sperytilecrystal

Platinumsi

foundinseveral

mineraslone
,

beingsperry
eti.l

Thisis thealrgest

knownsperr teyil

crystalo, f undin South

irfAcac. 1924.

Platinumaigrns

Mostpaltni umminerasl

Sivler

occurastiny granis in

branches

nickeldeposits.These

,O
ylcon
asilaas

granisarefrom Coolmbai,

inthis specimen

wherepaltinumwas

fromCopiapo,

irstreportedni the

Chilesi,vler

18thcen
.yurt

ocursin

e,dcaietl

barnckehil-

Imperaicoi
l ns Platinumnugget

dendrticforms.

Platniumhas Largenuggetsof palntium

 OceanofPDF.com

Gold

o T ,dya this metal is used in jewellery

, electronics, and dentistry,

but more than half the gold mined is buried again – in bank

vaults, as investments.

Crystalline

chcaoletpyir

Fool’sgold

Pytrie and

SouthAfrcia

schca’oleptyri

r T aditionalgold mines

brassyolocur

werealbouretni nvsie.

canbe mastkein

TheGreatGold Rush

forgold.But

Porspectorsol ckedto

chcaolpyrtei,he

pangold in19thc-entury

mainore, ofopper
c

ofCiralniaUSA
, on,
;ukthe Y

ismore greensih-

Canada;and Austrai.l

ow,l leymore btriel,

andharder than

goldthough
, not

ashard aspyr
e.ti

Pytrie

i e V ngold

Pyritemostly

Goldmay

formscubiccrystasl.

occurin

Crystalnil e rocks htat

quartzveins.It is

don’tshowa crystal

ed
eaxrct bycrushing

habitare caeld

theoreo f retaonrectnc,

. “mPyatrisevie”is

whichis thensmetld.

closerinoc olurto

“whitegold” orelectrum,

t u T ankhamuns’

analloy m
()xtuierfo

arclol

goldand
, thansvlier

Goldgrains
 OceanofPDF.com

gn i t tuC gn i hs i dl nopa

The earliest gemstones were rubbed togetherto

produce a smooth surface,which could then be

engraved. Skilled workers, called lapidaries, cut and

polish gemstones, choosing the best way otkeep

them as large and beautiful as possible, sometimes

helped by using computers.

Hollowdrum

Cutting gems

eoadtr byrollers

Whenstones
mined,
often
gem
look

ocredull.
ate a desirable,
T sparkling

gem, the lapidary must cut and

polish it to enhance itsnatural

qualities, allowing for any flaws within.

Rle
ol r s

Thehardest cut

Roughdiamonds aremarkedwith

indianinkofebrethe rist berak or

cutismade.
 OceanofPDF.com

Roughquartz erady ot bebroken

fortumblingand polsihing

Amethyst

Amethyst makesattractive

polishedstones, with areas of

lighter and darker purple and

colourless patches.

Polsihedrock crystal

oloc(urlessquartz)

Polsihed

Necklace

amethyst

Colourful tumbled

stonescan be made into

necklaces and bracelets.

Fragments

ofamethyst

Carved

aalbaster

ostne

Carved stones

Cameos have a raised

nItagoil

design, carved in rel, ief

seal

while intaglios are

hollowed out.

Intagloishowing
 OceanofPDF.com

n i t r a t Sg l nlo iotace

Collecting mineral and rock specimens is a rewarding and

popular pastime. It dates back ot the amateur geologists of the

19thcentury, many of whom amassed impressivecollections.

Geologists’

Schatelwith

hammer

rockspecimens

(0g/1
5. k) bl

Careful planning

Plan any field work andollecting

c trips in

Geologists’

advance, using geological guidebooks, maps,

trimming

andinternetsearchesbefore your visit.

hammer

Download useful apps (such as a compass and

map)ontoyour phone. Make sure you can get

a signal and your phone is charged. Get

permission to visit any areaorsite on

private land. Check tide times if

Collecting

you are visiting a beachto

makesure you don’t

kit

get cut off by the

Packa geological

tides. Never enter

hammer but

old mines or cave

don’t hammer

systems. Do tell
unnecessaryl.i

someone where you

a T kephotosrather

are going and when

than specimens

youexpectto be back.
unless you really

needafew

Map

specimensfor

your collection.
 OceanofPDF.com

Wanr ing Recording a find

When rock
- ollecting,
c thereareertain
c Number the specimen by placing a label with the

rules you should follow at all times: specimenbeforeyouwrap it. Make a noteof exactly

check thatollecting
c is allowed and whereyoufound it, with a note or sketchin your

always obey the Countryside Code, ask notebook, or make notesandtakeaphoto as a

permissionbeforeentering privateland, r reminder

ytoinclude
. T something such as a coin

avoid disturbing wildlif

e,wear suitable or your hammer in your phototo show the size of

clothing, use proper equipment, and rocks and where

avoidcreating hazardsorf others. youfound the

specimen,

beforeyou

Pen

Identification

In the field, use a x10

magnification hand lens.

Indoors, a binocular
Noetbook

scopewillmicro
reveal

finer details.

Ca

Pencli

Spatuals

forine

Surgcialkn
orfief

work,

nieprepartoary

suchas

workono f ssisl

cutting

around

a r T nsporting

oisfsl

Wrapeach specimen

individually to avoid

chipping or scratching.

A s c r y stalgroups are

eePtal

usually very fragile,

efknifor

pack them in

cartexting

tubes or boxes with

smallcrystals

wrapping and carry

fromsofot f ssisl

in collecting bags.
 OceanofPDF.com

duoiyD ?wonk

A M A Z I N GACTS
F

etfA r astronauts returned from the Moon, On some coastlines made up of soft

scientists discoveredthat the most rocks, the sea carves away metresof

common type of lunar rock is a basalt also land every. Some

year villages, such as

foundon Earth. DunwichinSuffol k , U K , have partly

fallenintothe sea as cliffsollapsed.

c

Icecan shatt
errock. Granit
e, one of

thehardestrocks, can be split by wat

er

in cracks, expanding as it freez

es. The

combined weight and movement of

aglacier(a river ofe)iccan hollow

out a whole mountainside.

Unaware it was poisonous, women in

ancientRome used the mineral arsenic

asacosmeticto whitentheir skin.

Spdierfossiziledinamber

Graphite, used in pencils, is also used

in nuclear power stations. Huge graphite

Amberformed when sticky resin oo

zed

rodshelptocontrol the speed of

from trees millions of years ago,sometimes

nuclear reactions in the react

ororce.

trapping insects bef

oreit hardened.

Obsidian is a black, volcanic rock that is

Thedeeperinto the crust a tunnel goes,

so shiny that it was used as a mirror in

thehott
er it bec
omes. The deepest gold

ancient times.

mines in South Africahaveto becooled

Rock sareconstantly

down artificially so that people are able

changed by erosion and

toworkinthem.

ecorf s deep inside Earth.

reW
ta and wind have

carved out this sandstone

arch over millions of years.

Obsidain
 OceanofPDF.com

Q U E S T I O N S A N D A N S W E RS

What are the mostommon

c rocks in

Earth’s crust?

l oV canic rocks, such as basalt, are the most

commoncrustal rocks. Basaltforms from

the more fluid type of lavaasitcools and

hardens. It makes up the ocean floors,

whichcover 68percent of Earth’ssurfac.e

Howdoweknow that dinosaursxist

eed?

Dinosaur bones and teeth have beenound

f

zeFiodlsifootprnitofa dinosaur

asfossils all over the world (ashaveother

animals and plants). Eventheirfootprints

and dung have been preserved in rock.

Ifpumice is a rock, howome
c itcanfloat

onwater?

Pumice is hardened lava froth from

volcanoes on land and under the sea. It is

full of tiny air bubbles – the air trapped

inside these bubbles makes pumic

e light

enough to float.onrwat
e

What made the stripes on the desert

rocks in Utah,? USA

The rocks are made of layers ofsandstone.

Chinesenephrtiedragon

Over millions of years, hot days,cold nights,

floods,andstorms have worn away the

softer layers of rock, creatingstripes in

What is jade, and why has it got more

the landscape.

than one name

?

In 1863, this rock wasound

f to be two
What are the oldest rocks on Earth
?

difeerntminerals, now called jadeite

The oldest known rocks came

and nephrite.

fromspaceasmeteorites.

This chondrite is 4,600

Why are the pebbles on a beach so many

million years old, as old as

differentcolours?

the Earth, and even older

Pebblesare made up of many types of rock, than the first rockofotrm

 OceanofPDF.com

k c o Rro

? l a r en im

Geologists classify rocksaccording to the way

in which they wereormed,

f in three main types:

Geologists’

igneous, metamorphic, and sedimentary rocks.

otsol

IDENTIFYING ROCKS

Igneousrocks Metamorphicorcks

Igneousrocks aremadefrom Newmetamorphic rocks

ormf

hot,moltenock
r from deepwithin whensedimentar
, y igneous, or

Earththathasoc oledand soldi ied. existnigmetamorphicrocksare

Themore slowly arockcoolsand oafnsrtrmedbyorhteaand/

solidiies,thelarger thecrystals pressureinEarth’scrust.Dierent

canform. minerorm
aslf dependingon the

amountoforhteaprand/
essure.

Large cry ats ls

ofquartz,

feldspar
, and

micaformed

as the rock

cooled wly
slo

Getanri

Crinkled

layers

Foldedschist

Fine grain siz

e

Large cry ats ls

 OceanofPDF.com

IDENTIFYING MINERALS

Each mineral is different and may have acharacteristic

colour or crystal shape that helps us identify it. S ome

formcrystals larger than a human, othersorm

f

as sheets or lumpy masses, or grow as crusts on rocks.

Vitreous,

or glassy
,

lustre

Gold

Quartz

Goldis apreciousmetal andarare

Oneof themostcommonminerals,

natvieelement.Usuaylfoundas

quartzoccursin many rocks,etfon in

yelol wspecks inocks,

r tioften

mineraveil ns withmetaolres.Quartz

growswithquartz in mineraveil ns.

crystals usualyl have sixsideswith a

Oconal
asi lygoldo f rmslarge

topshapedkile apyramdi.

crystalnil e nuggets.

Pearly

lustre on

c r y s atls

Massof tabular

Cockscombbarite

albite cry ats ls

Barorms
tief ni many envroinments,

fromhotvolcanic sprnigs ot mnieral

 OceanofPDF.com

dntiuoF

Rocks are all around you, on the ground and in walls,

buildings, and sculptures. The best way to find out

more about them is to collect them. Going on a trip

or holiday can also provide a chance to find different

rocks and discover new types of landscape. Here

Collecting pebbles you will find suggestions for museum collections

Pebblebeaches, lakesides, and river banks are

and other good places ot visit, as well as a list of

good placesot lookorf specimens. See how

manycolours and types you can find. Always

useful websites.

takecarenear. wat
re

Gathering information

Visit your local natural histo r y or geological

museum to see rocks and minerals, rare and

common. Many museums also have display s on

volcanoes, earthquakes, and rocks from space.

 OceanofPDF.com

USEFUL WEBSITES

• Acess one of the world’s finest Mineralogyollections

c on the

websiteoftheNaturalHistory Museum, London:

. www nhm.ac.uk/
our-science/
c ollection
m/s ineralogy-

collections.html

• Rockwacth is an online club for young geologists and includes a

library and games:

. www rockwatch.org.uk

• u Tu o Y be series EveryockR Has aoStr y by. Ethan

Prof Baxt
erfrom

BostonCollege helps children unearth the wonders of Earth

through an online curriculum:

.youtube.
wwwc com/ hannel/UCl0Zrg9JFh5o4SPg94veh0w

Badlands National Par k , S o uth Dakota, USA

 OceanofPDF.com

yrassolG

ABRASOI N

Eroos,winidoceiar,ulden
serdebywiwttah

sedm
i enats,ndscrapnigorubbnigaganisthe

eofroacfuskr.

ACCIULAR

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dkeoril-f

YOLLA

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ircem
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,ehtslsatimxtuierotwfotypesofmae.lt

ELEMENT

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CABOCHON

retmstam
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sipeslrubstanc.e

asmoothd,omedupepcaewirsutrfhout

est. acnfy
EROSOIN

ThewenaigrawayoforckesoncEatrhsu’rf

T CARA

,anc.edi e,wnrwdi,atbygartyvi

Thestandadrmaesurogwfhotfeir

A V E PORITE

poeurcoitsneOs.nemtecequal
tirar s

7002.g0(sAo.zl)usedtodescrbi e
or
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theputyriofgodlp;uregodsl2i4.tcar

EXTRUVSIEROCK
G A V CELEA

m
Foredwhenmgamauvp,teraswlchi

Thewayacrystalspltisapartalong

. eca hstfeusrloac

aitcernwd-elnfiedpalnoersdancig

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CORE

Thearofniandcnkeilthatesmup
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E CA F T

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ne.st

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i eter

FIRE

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ngIemotsnerfsi,eenasasparkelofcolurs

ThethniouteayrleoEfarthtI.vareisni

causedbythedsipersoinogifhlers
taseinta

thciknesbetweensxiand70km
 OceanofPDF.com

POROUS

etiM
orete

, ,orAobtheltoeudfrlaibs.esobrwat ari

PORPHYRY

Angineousorckcongaiyfnrltirge

crystaostnlsetianfiermatxri.

MNIERAL

T A PRECPITIION

yaAunrltaolcunrigni,organcisodilwtih

Achemecpasilordcunrigwhcihasoldi

atencrtndiecisfhtrisa,ructchascrystal

usba,ntcseucham
sil seid,edporfomsti

sturctuerandchemcialcompotins.

asou.lotinsu,cham
sil ec-rihewrat

MNIERALVENI

PYROCLASTCIROCK

Acarnckorieclkdfibyhoutfdlis’

Pyrocalsctimeanersnfib“-a”nordkdescrbi es

mnieradlepotsi.

talhefargmenftrsockp,um,acenidsodilava

MOHSSCALE
thatmaybxpeoldedoutofacnov.l

Ascaelodfhanresfrom101tbasedonten

RESNI

mnM
iesar.nliearsolfahgihernumberareable

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ersf some

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ed
denotafmber

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asagem.

eM
dt,m
eladnoteqiaudlibythegaera,

ROCK

especyalirocks.

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fergatnieraplarcteils.

T A N IVEELEMENT

Anelmenthatocalusrytnalieatefresta

anddoroem
snotpa
f torafcompound.

NODULE

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ound
lfanier ni

sedm
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OOLITH

Smor,ulandedgm
arnisliestones.

A P OQUE

reMtatilhatdogetilsnhotpasthrought.i

OPTCIALPROPTEIRS

Thevoairuseopfctaiflecsptorducedagsilht

pasesthroughmnierasTl. hsioneofthe

properteisuosehdeptldietfnyimnierasl.

eshangi
Stacitl ng orfm theoof
r foaevac
 OceanofPDF.com

gastropod limest
one

21, 39

magma
, 10,16,
7 18

gemstones 6, 50–55

magnetite 15,49

cutting and polishing 60–61

make-up 13,33

x edn I geological proc

esses 10

malachite33

geologists6,62
charcoal32

AB

marble 24, 26–27

Giant CrystalCave,
chrysoprase 53

adzes29 marine organisms

Mexico44
cinnabar 33, 57

Airfcan marble 27
(microscopic) 21

Giant’s Causeway
, Northern
caly9,11, 20, 43

agate52, 53
Mars meteorite41

Ireland 16–17
forart32

agglomerat
e 18
melting rocks 10

glaciers 13
roofing35

albite76

mercury 57

glass 15, 35
coal
, 36–37
7

alloys 56, 57

mesolite9

see also

gneiss 10, 11, 25, 66

charco al

aluminium 56

Mesolithictools and weapons

gold 6,,7659
collecting2–6
63

amber 14, 64

29

Grand Canyon, USA

conglomerate21, 66

amethyst 55, 16

metamorphicrocks 11, 24–25,

20–21
continentalples
at 6

ammonites 21, 39

66

granite, 7 15, 16, 34

copper33,
, 5647

amphiboles42

amphiboles in 42

identifying 66
corundum 45, 51,67

anthraci
, 37
et7

local 14

and its minerals 8

crystals

aphthitalite 19

meteoriest 40–41,65

weathered13
giant 9

Aragonite 4 6

mica 46

graphite 4 8 , 6 4
growth of 46–47

arrowheads29

biotite 16,25,42

GeratWall of China 35
habits 6

arsenic 33, 64

ingranite 8

gypsum9, 20, 44
quartz, 4174

ash, volcanic 18, 20

specific gravity 49

symmetry 44

asteroids41

Michelangelo 26

HIJKL

twinning 45

augit
,e4317

migmatite 10,25

see also

gemstones

halite(rock salt) 20,

axes28–29
, 30

minerals ,8–9
42–43

daggers 29

, 7476

azurite33, 45

in basic rocks 43

desert, weathering 12

Halley’s Comet41

baryte 45,48,67

carbonat
es and

diamond 48,, 50
49

handaxes28

basalt 8, 10,, 43,

17

clays 43

digging stick 30

hematite 33, 46, 56

64–65, 66

in granitic rocks42

dinosaur bones 39

hornfels24

battleaxes30

identifying 67

diorite304,2

iceerosion 13

b e r y l 4 4,50,76

ores6,56–57

igneous or ck, 16–17

s, 66
7
biotite 8, 16, 25, 42

pigment32

EFG

amphiboles in 42
body and rock art 32–33

properties of 48–49

extrusive/intrusive 10
Earth 6–7
breccia 18, 21,, 66
27

secondary 13

intaglio61
structure 6
bricks 35

from volcanic

iron 33, 56
bronze56 Ease Gill Caves, England 23

gases 19

ironmeteorite40,41
BronzeAge weapons eclogite24

see

mining,forcoal coal

jade 52, 53, 65

andtools29
, 30–31 Egyptian goldsmithing 59

Mohs scale 48, 49

buildingstones 34–35 jadeite65

Egyptian orange33

Moon rocks 41, 6 4

see also

Byzantineer lic 55 jade

emerald 45, 50

mosaic floors 34

jet 36
erosion 12, 13

mudstone20,21

CD

kimberlite 50
evaporites20

museums 68–69

lapis lazuli 33, 52

eldsp
f ar 8,
, 16–17
,92–43,
4 76

calcite,9 22, 43, 48, 67

lavas
, 7, 1 718
feldspathoids 43

cameos53,61

NO

basaltic 19
flint

carbon, 48
37

Neolithic axes 30

nodules 15 viscous19

carbonates 43

nephrite 53, 65

silica 21 lead57

carnelian 53

nickel40,57

tools28–29 limestone

Carraramarble, Italy 26

NotreDame,Paris 35

fools’ gold 59 algal 21

cassiterite6,75

nummulite 34

foarmnifiera 21, 34 forbuilding 34–35

cave painting 23

obsidian 16,,,9219 6 4
fossils 6, 38–39
,64–65 caves20,22–23
cement35

identifying 66
fossilizedwood 36 fossils in 21, 38, 39
chalcedony 53

oceanicpaltes 6
limestone21, 34 landscapes 22–23
chalcopyriet46,, 74 56, 59

see also

ochre33
coal ore minerals in57
chalk

oil shale 36
gabbro10,,71 43, 66 sedimentary rock 7
cliffs 15

see also

marble olivine 8, 15, 40, 43

identifying 66 galena, 749
5

limestone21 galvanizing 57 lunar rock opal 51

see

pigment31,23 garnet 24, 25, 46, 55 Moonrocks ore minerals 56–57