Sterling Silver & Genuine Large Cabachon Black Onyx Ring Polished large Black Onyx Gemstone. Measures 25 x 15 MM High style... large ring Size 7, 8, 9 This ring can be sized Great statement piece! Great for the index finger! Great color for fashions. Add this piece to your wardrobe! This ring is also available in: Bloodstone, Tigereye and Turquoise Please see all the Black Onyx pieces listed.