Interesting Sphalerite Crystal from Germeny Minerals 9:57 PM A+ A- Print Email Sphalerite Formula: ZnS System: Isometric Colour: Yellow, light to dark ... Lustre: Adamantine, Resinous Hardness: 3½ - 4 From: Pit aid (Halsbrücke, Germany). Photo Credit: Lászlo Tóth