Stibnite
Appearance
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Stibnite_-_Herja_mine%2C_Maramures%2C_Romania.jpg/220px-Stibnite_-_Herja_mine%2C_Maramures%2C_Romania.jpg)
Stibnite is a mineral. Its chemical formula is Sb2S3. It is the main ore of antimony. The American Museum of Natural History has a huge crystal of stibnite. Stibnite is soft, with a Mohs hardness of 2. Its specific gravity is 4.63.