Sphalerite

Sphalerite is a mineral that is composed of zinc sulfide and is commonly found in sedimentary, igneous, and metamorphic rocks. It is often associated with other minerals such as galena and pyrite, and is an important ore of zinc.
The color of sphalerite can range from yellow to brown to black, and it has a distinctive resinous or greasy luster. It is relatively soft, with a hardness of 3.5 to 4 on the Mohs scale, and has a specific gravity of around 3.9 to 4.1.
Sphalerite is often used in the production of zinc metal, which has a variety of industrial applications. It is also sometimes used as a gemstone, although its softness and tendency to degrade over time make it less desirable for this purpose than other minerals. Overall, sphalerite is an important mineral both economically and scientifically, and its distinctive properties make it a fascinating subject for study.