Sphalerite is a group of sulfide minerals. It is a zinc sulfide mineral. Pure sphalerite is colorless and rare. In general, the presence of iron ranges from pale green to yellow to brown to black. The color changes as the iron content increases. When the iron content is high, it turns into an opaque black marmite. Sphalerite derives its name from the Greek word Spaleros, which means "deceptive" because its shiny dark crystals can be mistaken for other minerals.
It is very common to find sphalerite formed from minerals such as fluorite, pyrite, galena, dolomite, quartz, and calcite. It often produces thick crystalline or bulky or banded, botryoidal, or stalactic aggregates. Sphalerite is a common mineral found all over the world, with excellent specimens coming from Mexico, Morocco, Switzerland, Franklin, and New Jersey.