Rare Cobalto Calcite Druzy & Sterling Silver Ring Size 5.75 Rough Cobalto Calcite Druzy .925 Sterling Silver; Weight: 4.9 grams Genuine Stone. Each item comes shipped in a jewelry box. You are looking at a one of a kind piece, the pictured jewelry will be the same exact piece you'll receive. Each item is designed and handcrafted by our artisans.