Jet

Photo of a jet brooch
Photo by Wikipedia
Attribution-Sharealike

Jet, also called lignite, is not a true mineral or stone. It is fossilised decaying wood. The original structure of the wood can be seen in jet under a microscope.
Jet is black and has been used to make jewellery for many years. It was quite popular to make mourning jewellery, for wearing at funerals.

Edit this word: