Jet

Jet is organic in origin. Like coal, it was formed from the remains of wood immersed in stagnant water millions of years ago, then compacted and fossilized by the pressures of burial. Jet is black or dark brown but may contain pyrite inclusions which have a brassy color and metallic luster. Jet takes a good polish and is often faceted. When burned or touches with a hot needle, it exudes the characteristic smell of coal.

Jet was popular for mourning jewelry in the 19^th century due to its somber color and modest appearance. Traditionally, it has been fashioned into rosaries for monks. Jet has also been known as black amber, as it may induce an electric charge, like that of amber, when rubbed. Powdered jet added to water was believed to have medicinal powers.

Gems made from jet take a good polish. Because the jet is organic, it may dry out, causing the surface to crack. Jet usually is opaque and has a velvety luster. Faceting can add life to an otherwise dull gem. The rough jet occurs as a fine-grained, fragile specimen with rough, cracked surfaces. It has a dull and earthy luster before polishing.

Jet is light to wear and so particularly suitable for earrings. During the Victorian era in Britain, it was very popular for mourning jewelry. Some jet specimens have trapped ammonite and bivalve fossils. These are evidence of its organic origin.

Jet is commonly drilled and faceted as beads. Turkey is the most popular source of beads and necklaces made out of jets.

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Occurrence

Evidence suggests that the jet has been mined since about 1400 BC. However, worked pieces of jet have been found in prehistoric burial mounds. During the Roman occupation of the British Isles, worked pieces of the jet were shipped to Rome. Perhaps the most famous historical source is Whitby in Yorkshire, England. There, much of the jet was popular for the mourning jewelry of the 19th century originated. During this time, the mining and fashioning of jets provided the town with much of its income.

Other localities include the USA, Turkey, China, the former USSR, India, Poland, Germany, France, and Spain.