วัสดุเจ็ต (หินเจ็ต)Jet

The earliest worked jet anybody has is a model of a botfly larva from about 10,000 BCE, found in Baden-Wurttemberg among the Venuses of Petersfels. Britain has used it since the Neolithic, through the Bronze Age for necklace beads, then not at all through the Iron Age, until it came back in Roman Britain in the early third century CE. Whitby jet was collected by beachcombing and worked at Eboracum, modern York, into rings, hair pins, beads, bracelets, bangles, necklaces and pendants. Jet pendants were cut cameo-style, and the Medusa head was a favourite subject — a gorgon face carved from fossil wood, aimed at whoever looked at the wearer.

The Roman period is where jet is named as a magical material outright, used in amulets and pendants for its supposed protective qualities and its ability to deflect the gaze of the evil eye. Pliny the Elder gives the claims: "the kindling of jet drives off snakes and relieves suffocation of the uterus. Its fumes detect attempts to simulate a disabling illness or a state of virginity." Solinus and Galen refer to it too.

Then it becomes a pilgrim's stone. At the end of the Middle Ages the trade in religious objects and jet amulets reached great development at Santiago de Compostela, sold to pilgrims walking the Camino; the workshops were at Santiago, the deposits up the coast in Asturias, where beads and rosary beads were also cut. Near Erzurum in Turkey the same material is oltu stone and is made into prayer beads. In New Mexico, Navajo and Pueblo people were using regionally mined jet for jewellery and to ornament weapons when Spanish explorers reached the area in the 1500s.

Victorian Britain turned it into mourning. Queen Victoria wore a jet necklace as part of mourning dress in the 1850s and again for Prince Albert, and the trade followed her. Use peaked in the early 1870s; Whitby went from more than a thousand workers in the trade to three hundred by 1884, as Art Nouveau turned away from black jewellery; by the end of the Second World War three jewellers were left, and the industry ended with them.

Jet jewellery came back into fashion in the 1980s and new jewellers took up production. The Puerto Rican azabache bracelet is the material's busiest survival as a charm: it carries a black or red coral amulet in the shape of a fist with the index-finger knuckle protruding, and it is the commonest protection put on an infant there. Imitations are old and numerous — glass sold as French jet or Vauxhall glass, ebonite that fades, anthracite, offcuts bound with glue and moulded, and museum reproductions in epoxy resin.