Sphalerite, Zinc sulphide, ZnS, Dylife mine,Central Wales Orefield. The sphalerite is massive,with no discernable individual crystals,and enclosing one or two shards of original host rock,indicating an earlier episode of hydraulic brecciation. Also in the specimens is an equal amount of quartz,which does have intergrown crystals,albeit not very well defined, which suggests that the quartz grew into cavities after the original brecciation. Also observed on the surface are a few small deposits of galena,and a vey small deposit of chalcopyrite.