The facts
What jet actually is
Mineralogically, jet is lignite — fossilised wood — Carbon with hydrocarbons, crystallising in the amorphous system.
The colour is caused by carbon. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.64–1.68, and the specific gravity sits near 1.30–1.35; cleavage is none.
Where jet comes from
The recognised sources are Whitby, Yorkshire, England, Asturias, Spain and Colorado, USA.
Origin affects price in this material, so we name the locality on every quote rather than the country. "African" or "Asian" tells a buyer nothing.
Is jet treated?
None. Vulcanite, glass and black plastic imitate it.
That makes disclosure simple: there is nothing to declare. It also means a seller offering a "treated" version of this material is offering something else.
What jet is confused with
The usual confusions are Vulcanite, Black glass, Obsidian and Plastic.
The separation is rarely a matter of opinion: refractive index 1.64–1.68 and specific gravity 1.30–1.35 settle most of it in a minute, and magnification settles the rest.
What jet is used for
Jet is bought by jewellery, memorials and carving and sculpture — and each of those trades wants a different form of the same material.
We quote each application in the unit that trade actually buys in, by the carat, by the piece or by the block.
Durability and care
Hardness 2.5–4; cleavage none. That combination decides what it can safely be set into.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What jet costs
Indicative pricing for jet is $1–50/g.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is jet treated?
None. Vulcanite, glass and black plastic imitate it.
Where does jet come from?
Whitby, Yorkshire, England, Asturias, Spain and Colorado, USA. Origin affects price, so we name the locality rather than the country on every quote.
Is jet hard enough to wear every day?
Not really. At 2.5–4 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does jet cost?
Indicatively $1–50/g. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is jet confused with?
Most often Vulcanite, Black glass, Obsidian and Plastic. A refractive index of 1.64–1.68 and a specific gravity near 1.30–1.35 separate it quickly.
What is jet used for besides jewellery?
memorials and carving and sculpture. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for jet?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about jet