The markings on the formation of this sphalerite is amazing! From wispy brushstrokes to strong gashes; and those ultra sparkly pockets of druzy 🤩 Sphalerite is made up of zinc sulfide, the chief ore of zinc. In its black variety, Marmatite, the mineral contains high concentrations of iron and is sometimes called Black Jack. Sphalerite is also known as Zinc Blende.