Idrialite (named for the Idria Mine in Slovenia, the type locality) is a very RARE mineral of organic origin (hydrocarbon). The species is also known as curtisite, which was described from the Skaggs Springs Mine. It has been found in very few localities worldwide. Specimens rarely appear on the market. This is about as good as they get - the mineral does not form eye-visible crystals. Ex. Carlton Davis Collection.