jet

A rich black variety of lignite, taking a high polish, used for jewellery and ornaments, particularly in the 19th century when Whitby on the Yorkshire coast was an important centre of production.

Jet as a gem material was highly popular during the reign of Queen Victoria, who wore Whitby jet as part of her mourning dress. Jet was popular for mourning jewellery in the 19th century because of its sombre colour 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.