The facts
What plasma actually is
Mineralogically, plasma is chalcedony — SiO₂ with chlorite and amphibole inclusions, crystallising in the cryptocrystalline trigonal system.
The colour is caused by green from disseminated chlorite, actinolite and celadonite particles rather than a dissolved chromophore. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.530–1.539, and the specific gravity sits near 2.58–2.64; cleavage is none.
Where plasma comes from
The recognised sources are Kathiawar, Gujarat, India, Hunan, China and Rhine Valley, Germany.
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.
How plasma is treated
Untreated, though green-dyed chalcedony is sold under the name. Plasma without red spots is distinct from bloodstone, which is plasma with iron-oxide flecks; prase is a separate, usually paler green quartz.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What plasma is confused with
The usual confusions are Bloodstone, Prase, Chrysoprase and Dyed chalcedony.
The separation is rarely a matter of opinion: refractive index 1.530–1.539 and specific gravity 2.58–2.64 settle most of it in a minute, and magnification settles the rest.
What plasma is used for
Plasma is bought by carving and sculpture, decorative objects, jewellery and mineral collecting — 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 block, by the piece or by the carat.
Durability and care
Plasma is 6.5–7 on the Mohs scale, with none cleavage.
With no cleavage plane to worry about, the practical limit is abrasion rather than breakage, and it takes daily wear well.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What plasma costs
Indicative pricing for plasma is Cabochons 10–50 USD; antique intaglios far more.
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 plasma treated, and how?
Untreated, though green-dyed chalcedony is sold under the name. Plasma without red spots is distinct from bloodstone, which is plasma with iron-oxide flecks; prase is a separate, usually paler green quartz.
Where does plasma come from?
Kathiawar, Gujarat, India, Hunan, China and Rhine Valley, Germany. Origin affects price, so we name the locality rather than the country on every quote.
Is plasma hard enough to wear every day?
Yes. At 6.5–7 on the Mohs scale with no cleavage plane, it handles daily wear well. The practical limit is gradual abrasion rather than chipping.
How much does plasma cost?
Indicatively Cabochons 10–50 USD; antique intaglios far more. 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 plasma confused with?
Most often Bloodstone, Prase, Chrysoprase and Dyed chalcedony. A refractive index of 1.530–1.539 and a specific gravity near 2.58–2.64 separate it quickly.
What is plasma used for besides jewellery?
carving and sculpture, decorative objects and mineral collecting. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for plasma?
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 plasma