The facts
What montebrasite actually is
Mineralogically, montebrasite is amblygonite-montebrasite series — LiAl(PO₄)(OH,F), crystallising in the triclinic system.
The colour is caused by colourless to pale yellow or greenish; colour from trace Fe and Mn. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.594–1.622, and the specific gravity sits near 2.98–3.10; cleavage is perfect in one direction, good in two more.
Where montebrasite comes from
The recognised sources are Linópolis, Minas Gerais, Brazil, Mount Mica, Maine, USA and Nuristan, Afghanistan.
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 montebrasite is treated
Untreated. Most gems sold as 'amblygonite' are in fact montebrasite — the two are separated only by fluorine content. Perfect cleavage makes it a difficult stone to cut and set.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What montebrasite is confused with
The usual confusions are Amblygonite, Brazilianite, Quartz and Beryl.
The separation is rarely a matter of opinion: refractive index 1.594–1.622 and specific gravity 2.98–3.10 settle most of it in a minute, and magnification settles the rest.
What montebrasite is used for
Montebrasite is bought by mineral collecting, jewellery and technical and precision components — 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 specimen, by the carat or by the piece.
Durability and care
Hardness 5.5–6; cleavage perfect in one direction, good in two more. That combination decides what it can safely be set into.
Hardness is not the whole story. Perfect cleavage means the stone can split cleanly if struck along the wrong plane, whatever its Mohs number, so a protective setting matters more here than the hardness suggests.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What montebrasite costs
Indicative pricing for montebrasite is 20–120 USD/ct.
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 montebrasite treated, and how?
Untreated. Most gems sold as 'amblygonite' are in fact montebrasite — the two are separated only by fluorine content. Perfect cleavage makes it a difficult stone to cut and set.
Where does montebrasite come from?
Linópolis, Minas Gerais, Brazil, Mount Mica, Maine, USA and Nuristan, Afghanistan. Origin affects price, so we name the locality rather than the country on every quote.
Is montebrasite hard enough to wear every day?
With care. It is 5.5–6 on the Mohs scale, which is hard enough, but perfect in one direction, good in two more cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does montebrasite cost?
Indicatively 20–120 USD/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 montebrasite confused with?
Most often Amblygonite, Brazilianite, Quartz and Beryl. A refractive index of 1.594–1.622 and a specific gravity near 2.98–3.10 separate it quickly.
What is montebrasite used for besides jewellery?
mineral collecting and technical and precision components. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for montebrasite?
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 montebrasite