Gems : Jet

Jet has been mined since about 1500 BC, before recorded history, and jet items like beads, pendants and charms have been found in ancient burial mounds.
One of the organic gemstones, jet was formed from driftwood that was subjected to chemical action in stagnant water, and then to heat and pressure. Millions of years old, it’s surprisingly light and warm to the touch, and will usually create static electricity when rubbed.
Jet is, of course, black – anything absolutely black is called "jet black".
Jet was used by the Romans, who exported it from Whitby, and was also very popular with the Victorians. It has often been used in mourning jewellery, which may have made it slightly unfashionable. Being light, jet can be used for quite large pieces of jewellery. It takes a good polish, but is probably at its best when carved. Jet from Whitby is generally acclaimed to be the best in the world for jewellery and carving.