Gemstone: Black Onyx, Black Rutilated QuartzGemstone Shape: Round, Faceted RoundGemstone Size: 8 - 18 mmGemstone Total Weight: 230 caratsMetal: Sterling SilverClasp: Lobster ClawFinish: High PolishNecklace Dimensions: 18 mm wide x 18 inches long X 2 inches extensionModel No. OPN-3138