Rodolicoite Fe3+ PO4
c 2001-2005 Mineral Data Publishing, version 1
Crystal Data: Hexagonal. Point Group: 32. In microcrystalline nodules, intimately mixed
with grattarolaite, as crystallites to < 1000 Å.
Physical Properties: Tenacity: Brittle. Hardness = n.d. D(meas.) = n.d. D(calc.) = 3.04
Optical Properties: Opaque. Color: Reddish brown. Streak: Brown. Luster: Greasy.
Optical Class: Uniaxial. ω = n.d. = n.d.
Cell Data: Space Group: P 31 21 (synthetic). a = 5.048(3) c = 11.215(8) Z=3
X-ray Powder Pattern: Synthetic.
3.445 (100), 4.360 (19), 2.362 (14), 1.8846 (12), 2.180 (10), 1.4214 (10)
Chemistry: (1) Due to the tiny particle sizes (average about 260 Å) only bulk composition of
the mixture could be determined; this is compatible with a composition of Fe1.04 P0.96 O4.00 ; the
identity of the mineral rests also on its X-ray powder pattern compared to synthetic material.
Occurrence: Very rare, in microcrystalline nodules in lignite beds which appear to have
naturally burned.
Association: Grattarolaite, heterosite.
Distribution: From the Castelnuovo mine, Santa Barbara lignite district, 30 km southeast of
Florence, Florence, Italy.
Name: Honoring Francesco Rodolico (1905–1988), Professor of Mineralogy, Florence University,
Florence, Italy.
Type Material: Museum of Natural History, Florence University, Florence, Italy, 2087/RI.
References: (1) Cipriani, C., M. Mellini, G. Pratesi, and C. Viti (1997) Rodolicoite and
grattarolaite, two new phosphate minerals from Santa Barbara mine, Italy. Eur. J. Mineral.,
9, 1101–1106. (2) (1998) Amer. Mineral., 83, 654 (abs. ref. 1). (3) Arnold, H. (1986) Crystal
structure of FePO4 at 294 and 20 K. Zeits. Krist., 177, 139–142.
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