Formation: Volcanic craters and hydrothermal environments such as hot springs. Sulfur can form in a crystalline form as shown in the photograph above, or in matrix as in photo #2 below, and in massive forms as in the crusting deposit shown in photo #3 below.
Unusual Properties: One of the original ingredients of gunpowder, sulfur has been in imporant mineral for centuries. As a by-product it creates sulfuric acid also known as acid rain. And is used in a variety of chemical applications. With a hardness of 2 sulfur is not used in any jewelry applications, however fine transparent specimens such as shown above are a asset to any collection.