Jet is actually a highly compressed, extremely hard form of coal, which is, in turn, a form of carbon. It is actually lignite, a form of brown coal derived from buried driftwood. Albeit not very hard, jet is tough and is well polished easily.
Jet has a dull luster on its broken surfaces and is typically cut into beads, crosses, bracelets, cabochons, and other various decorative objects. Jet is typically inexpensive.
During the Victorian era, jet was a popular mourning gemstone, used to express grief at the death of a loved one.
