A stone that burns like coal, charges electrically when rubbed like amber, and polishes to a deep black shine: jet is one of the strangest materials of the old world. Romans and Vikings alike valued the “black amber” – and credited it with protective power. A look at a stone that is not really a stone at all.
Strictly speaking jet is not a mineral but a mineraloid – an especially pure, hard form of lignite (brown coal), formed from the wood of ancient conifers. The famous Whitby jet of northern England formed around 181 million years ago from trees resembling today's monkey-puzzle tree. The name goes back to the ancient town of Gagae in Asia Minor. Jet is deep black, very light, can be cut with tools and polished to a high shine – and smells of coal when heated.
The most astonishing thing: rub jet and it charges electrically, drawing small fibres – exactly like amber. These two “warm,” light stones, the black and the golden, belonged together in the North. Both felt different from metal or glass, both seemed to carry a hidden power. No wonder they were credited with protection.
In Roman Britain, jet was a fashion stone from the 3rd century onward: rings, hairpins, beads and pendants, often with the head of Medusa as a cameo. The raw material was gathered on the beach at Whitby and worked in nearby York (Eboracum) – where plenty of workshop waste was found. The Vikings, too, used jet: for rings and small animal figures, with snakes a frequent motif. The exact source of their jet is not certain, but Whitby is regarded as the most likely origin.
Antiquity already held jet to be magical – a protective stone against the “evil eye.” Pliny the Elder writes in his Natural History:
“The kindling of jet drives off snakes.” Pliny the Elder, Naturalis Historia, Book 36 (translation after Bostock & Riley 1855, public domain)
Such ideas – a black stone as a ban against poison, snakes and misfortune – lived on for centuries. That the Vikings carved snakes of all things into jet may point the same way: an image of danger, bound in a protecting stone.
The appeal of jet has stayed the same: a warm, deep-black stone, light to wear, beautifully polished. What amber and jet once were is today the joy of real natural material at the wrist or the neck. Whoever wants to know more about the jewellery and silver world of the North will find it in our pieces on the carnelian beads and on hacksilver.
Jet is a mineraloid – highly pure lignite from fossilised conifer wood, deep black, electrostatically chargeable, combustible. Whitby jet formed in the Early Jurassic (Toarcian, ~181 million years). In Roman Britain (from the 3rd c.) jet was a common gemstone, worked above all in York; raw material from Whitby. The Vikings made rings and small (often snake) figures of jet; the source is likely, but not certainly, Whitby. Ancient authors (Pliny, Solinus, Galen) credit it with protective/healing powers.
Not every “jet” is jet: in southern Britain, Kimmeridge shale was often used as black jewellery, and even Victorian archaeologists confused the materials. And the famous black “mourning jewellery” fashion (Queen Victoria, 19th c.) is NOT Viking-age but much younger. What is certain is that jet was really worked and worn in antiquity and the Viking Age; the protective magic is a handed-down belief, not proof of an effect.
Hacksilver – silver as currency · Carnelian – the Vikings' red beads · Viking jewellery · Norse gifts for women · Rune magic – alu, laukaʀ and the formula words.