Jet: meaning, history and care of an organic gem

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Jet is a black, light lignite, brilliant when polished, formed from fossilised wood. A stone of Victorian mourning and of ancient amulets, it needs special care.

Key points

Colour	Deep black, resinous to glassy lustre after polishing; brown streak
Nature	Compact lignite of plant origin (fossil wood): an organic, non-crystalline material
Mohs hardness	About 2.5 to 4: soft
Density	About 1.3: light and warm to the touch
Deposits	Whitby (England), Asturias and Teruel (Spain), Ariège (France, formerly)
Age	Jurassic (Whitby, Asturias) or Cretaceous (Teruel)
Common imitations	Black glass (“French jet”), vulcanite, plastics
Special feature	Becomes electrostatically charged when rubbed, like amber

What is jet?

Jet is an intense black, light and smooth to the touch. It is not a mineral in the strict sense: it is a compact variety of lignite, a kind of young coal, formed tens of millions of years ago when tree trunks were buried in mud and slowly transformed under pressure and heat. It is therefore of plant origin, like amber, and is classed among the organic gems.

Its hardness is low: it can be cut, carved and polished with ease, to a very bright lustre. The best-known quality deposits are at Whitby, on the Yorkshire coast in England, in the Asturias and in the Teruel region of Spain. In France, the mines of the Ariège (Pays d’Olmes) supported a real jet-cutting industry in the seventeenth and eighteenth centuries, before the local deposits were exhausted.

Its French name comes from the Latin gagates, itself borrowed from a town in Lycia, it is said, where it was mined; sources disagree on this etymology.

From prehistory to Victorian mourning

Jet has been used since prehistory for beads and amulets. In the Middle Ages it appears in objects of devotion, notably in Spain. But its golden age came in the nineteenth century. After the death of Prince Albert in 1861, Queen Victoria wore mourning for decades and adopted Whitby jet: jewellery, embroidery and black buttons became the sign of respectable mourning throughout Victorian England. At the height of the fashion, Whitby had more than two hundred workshops and shops.

Later, fashion turned away from strict mourning, and cheap imitations caused demand to collapse: only a few workshops remain today.

Traditional symbolism

According to traditions, jet is associated with mourning, memory, protection and grounding. In several regions of Europe, notably Spain, it was made into amulets, based on the belief that it kept the evil eye at bay. Its darkness, its warmth to the touch and its lightness evoke a link with the earth and the past.

These are cultural traditions. One cannot claim that a stone protects anyone, and jet has no proven effect on grief or health. It can, however, be an object of memory, worn in remembrance of a loved one, which gives it a genuinely personal meaning.

Traditional correspondences

Area	Common association
Chakra	Root
Element	Earth
Planet	Saturn, in several Western traditions (black, slowness, mourning)
Signs	Capricorn most often; the lists vary

For the first chakra, see the page root chakra. For protective stones, see protection.

How to use it

As a necklace or brooch in an old style: jet goes well with dark outfits and period jewellery.
As a memorial pendant: worn in memory of a loved one or in mourning, with its personal meaning.
As rosary or meditation beads: its lightness suits long necklaces.
As a display piece: fine antique pieces keep better when protected.

Avoid wearing it for sport, in the shower or at the sea. See also the guide to gemstone jewellery.

Care and cleansing

Jet is soft, light and organic: care for it as you would a pearl or a fine wood.

Cleaning: a soft, dry cloth; if needed, a very slightly damp one, followed by immediate drying. No soaking, no ultrasonic bath, no steam.
Solvents, perfumes, household products: to be avoided absolutely.
Sun and heat: avoid them. Jet can crack or lose its shine under strong heat.
Salt: to be avoided.
Storage: separately, in a soft cloth, so it is not scratched by other jewellery.
Symbolic cleansing: incense smoke or moonlight. See our cleansing guide.

Recognising genuine jet

Jet has always been imitated, even in Victorian times. The most common imitations:

“French jet” or “Paris jet”, which is in fact black glass. Heavier and colder to the touch, it may contain bubbles. Genuine jet leaves a brown streak on unglazed porcelain, glass a white one.
Vulcanite (hardened rubber, patented in 1844) and gutta-percha, mouldable materials produced in quantity. Over time, vulcanite often takes on khaki-brown reflections.
Modern plastics, very common in cheap jewellery.

Jet is very light: a glass bead of the same size is noticeably heavier. For an old or expensive piece, consult a gemmologist. The hot-needle test, which gives off a smell of burnt charcoal, damages the piece: do not carry it out yourself. See also the gemstone glossary.

How to choose

Look for a deep black and an even polish, free of cracks. Old Whitby pieces are sought after by collectors and cost a lot; new pieces of genuine jet remain rare. A very low price for a large “jet” necklace usually indicates an imitation.

For more resistant black alternatives, see black tourmaline, onyx or black obsidian.