The facts
What tremolite actually is
The species behind tremolite is tremolite (amphibole group), Ca₂Mg₅Si₈O₂₂(OH)₂; it forms in the monoclinic system.
Near-colourless when iron-free; green with Fe²⁺; chrome-tremolite green from Cr³⁺ is responsible for the colour — and the chromophore, not the name, is what decides whether a colour is stable.
On the instruments it reads a refractive index of 1.599–1.637 and a specific gravity of about 2.90–3.07, with perfect {110}, distinct {010} cleavage.
Where tremolite comes from
Commercial material comes from Val Tremola, St Gotthard, Switzerland (type locality), Mangari, Taita-Taveta, Kenya (chrome-tremolite) and Merelani, Tanzania.
Different localities give different colour and different clarity, and the trade prices them differently. We state which one.
How tremolite is treated
Untreated. The iron-free end member of the nephrite series. Asbestiform tremolite is a regulated hazardous material; only massive or crystalline non-fibrous material is cut.
We state the treatment on every stone, including when the honest answer is that it cannot be determined. A treatment disclosed is a fact; a treatment discovered later is a refund.
What tremolite is confused with
Watch for Nephrite, Actinolite, Diopside and Scapolite — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.599–1.637 and specific gravity 2.90–3.07 settle most of it in a minute, and magnification settles the rest.
What tremolite is used for
The trades that buy tremolite are mineral collecting, jewellery and carving and sculpture. They do not want the same thing, and they do not pay in the same unit.
We quote each application in the unit that trade actually buys in, by the specimen, by the carat or by the block.
Durability and care
Hardness 5–6; cleavage perfect {110}, distinct {010}. 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 tremolite costs
Expect roughly $5–80/ct, depending on quality.
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 tremolite treated, and how?
Untreated. The iron-free end member of the nephrite series. Asbestiform tremolite is a regulated hazardous material; only massive or crystalline non-fibrous material is cut.
Where does tremolite come from?
Val Tremola, St Gotthard, Switzerland (type locality), Mangari, Taita-Taveta, Kenya (chrome-tremolite) and Merelani, Tanzania. Origin affects price, so we name the locality rather than the country on every quote.
Is tremolite hard enough to wear every day?
Not really. At 5–6 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 tremolite cost?
Indicatively $5–80/ct. 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 tremolite confused with?
Most often Nephrite, Actinolite, Diopside and Scapolite. A refractive index of 1.599–1.637 and a specific gravity near 2.90–3.07 separate it quickly.
What is tremolite used for besides jewellery?
mineral collecting and carving and sculpture. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for tremolite?
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 tremolite