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A sample of jet
'Jet' is a geological material not considered a true
mineral, but rather a
mineraloid derived from decaying wood under extreme pressure, and thus organic. The English word-name "jet" derives from the French word for the same material: . Jet is either black or dark brown, but may contain
pyrite inclusions, which are of brassy color and metallic
lustre. The adjective ''jet-black'' is better-known perhaps than the substance from which the descriptive phrase derives.
[1]
Jet is a product of high pressure decomposition of wood from millions of years ago, commonly of the
Araucariaceae family. It is found in two forms, hard and soft. Hard jet is the result of the carbon compression and salt water; soft jet is the result of the carbon compression and fresh water. Jet is easily polished and is used in manufacturing
jewellery, according to the Whitby Museum, dating from 10,000 BC in parts of contemporary
Germany.
Jet as a
gem material was highly popular during the reign of
Queen Victoria, during which the Queen wore
Whitby jet as part of her mourning dress. Jet was popular for mourning
jewellery in the 19th century because of its sombre color and modest appearance, and it has been traditionally fashioned into
rosaries for monks. In the
United States, long
necklaces of jet beads were very popular during the
1920s, or
Roaring Twenties, when women and young
flappers would wear multiple strands of jet beads stretching from the neckline to the waistline. In these necklaces, the jet was strung using heavy cotton thread; small knots were made on either side of each bead to keep the beads spaced evenly, much in the same way that fine
pearl necklaces are made. 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 or wine was believed to have
medicinal powers.
Although now much less popular, authentic jet jewels are valued by collectors.
Anthracite (hard
coal) and
vulcanite are similar materials that have been used to imitate fine jet: these imitations are not always easy to distinguish from the real thing. Unlike black
glass which is cool to the touch, jet is not, due to its lesser
thermal conductivity. Also, the structure of jet (which is remarkably like the wood that it is derived from) can be seen under 120X or greater
microscopes.
External links
★
Whitby Jet
★
Jet, the fossilized wood, the Asturian Jet in the Jurassic.
References
1. http://www.word-detective.com/120505.html#jet