Description | This sample contains brown-yellow sphalerite. Sphalerite has composition (Zn,Fe)S (zinc iron sulfide). It typically has a nice adamantine luster, sometimes described as being “resinous.” It may sparkle owing to its unusually high index of refraction and may show fire greater than diamond's. Transparent sphalerite has been cut for gemstones, but its cleavage and softness limit its use as a gemstone to collectors only. Sphalerite is a principle or mineral of zinc. This specimen, about 8 cm across comes from the lead-zinc mining district near Joplin, Missouri. |