Sphalerite is found in metamorphic, igneous, and sedimentary rocks in many parts of the world. The name sphalerite is from the Greek word "sphaleros" which means deceiving or treacherous. Most of these specimens are mixed with Calcite.
Also known as zinc blende and blackjack, Sphalerite is a zinc sulfide mineral that crystallizes in the form of masses, botryoidal, cubes, tetrahedral crystals, and dodecahedral crystals. Its most commonly silver and grey, but can also be seen as red, black, yellow, brown, green, and colorless. Sphalerite got its name from it constantly being confused with Galena. It’s very common to find Sphalerite formed with a variety of minerals such as Fluorite, Pyrite, Galena, Dolomite, Quartz, and Calcite.
This is a product of nature. Sizes and colors vary.