At the top of this matrix is a cluster of BIG sphalerites, measuring to 4 cm across. They crown a matrix of white dolomite sprinkled with smaller sphalerites and little brassy chalcopyrites. Big sphalerites such as this from Oklahoma are not common at all on the market! These are complete except for at the very back where they contacted matrix. Classic mid-1900s Tri-State district material! Ex. Feist Collection