Sphalerite:
Sphalerite is a rare natural gemstone. The color of Sphalerite can black, brown, orange, orangeish red, yellow, green, white gray or colorless. Sphalerite has a hardness of 3.5 to 4 on the Mohs scale. Sphalerite is one of the most beautiful gemstones when faceted. Sphalerite is a true collectors gemstone.