Costume Jewelry: "Whenever you notice it looking dull," says Argonish. If you notice your ring starting to lose its shine, or if it looks particularly dirty, don’t wait—clean it right away.

The 26-carat ring was first purchased in the 1980s by an anonymous seller, who bought the jewel at a car boot sale, under the assumption that it was a piece of costume jewelry.

One lucky woman who paid $15 for a large "costume jewelry" ring got the surprise of her life after learning the ring is worth way, way, WAY more than that. Thirty years ago, an unnamed owner ...

A $13 stone assumed to be costume jewelry ended up being a precious stone. One lucky woman unknowingly bought a 26-carat diamond for $13. Wednesday it sold for nearly $850,000.

A diamond ring purchased for ‎£10 ($13) has sold for £656,750 ($847,667) — roughly double its initial estimated value of £250,000 ($325,000) to £350,000 ($456,000) — at the Sotheby’s ...

Avoid soaking costume jewelry, as the adhesive and dyes used in these pieces can be sensitive to water. Buff the Ring: After cleaning, buff your costume jewelry with a dry polishing cloth to ...