Sphalerite

Two samples of yellow granular Sphalerite with a submetallic to adamantine lustre. Sphalerite (ZnS) can be yellow, red, brown, green, black, white (rare) or grey (Cleiophane) in colour. Lustre can be resinous, adamantine or submetallic and streak is light brown and will always be lighter than the colour of the mineral. Hardness is 3 1/2 to 4 and cleavage is perfect in six directions. Sphalerite is usually found as tetrahedral and dodecahedral forms with rounded faces but can also be cleavage masses, granular, compact and botryoidal.