The facts
What bertrandite actually is
Bertrandite is classified as beryllium silicate, with the composition Be₄Si₂O₇(OH)₂. It crystallises in the orthorhombic system.
Colour comes from colourless to pale yellow; no gem chromophore, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.583–1.614. Specific gravity around 2.59–2.60. Cleavage: perfect in one direction. Those three numbers separate it from most of what imitates it.
Where bertrandite comes from
Bertrandite is produced at Spor Mountain, Juab County, Utah, USA, Mount Antero, Chaffee County, Colorado, USA and Golconda, Minas Gerais, Brazil.
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
How bertrandite is treated
Untreated. The world's main beryllium ore at Spor Mountain, where the associated opalised fluorite is sold as Tiffany Stone. Faceted bertrandite is tiny and very rare.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What bertrandite is confused with
In the trade bertrandite is most often mistaken for, or substituted by, Phenakite, Beryl, Danburite or Herderite.
The separation is rarely a matter of opinion: refractive index 1.583–1.614 and specific gravity 2.59–2.60 settle most of it in a minute, and magnification settles the rest.
What bertrandite is used for
Demand for bertrandite comes from mineral collecting and heavy industry, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the specimen or by the tonne.
Durability and care
Bertrandite is 6–7 on the Mohs scale, with perfect in one direction cleavage.
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 bertrandite costs
As a guide, bertrandite trades around Specimens 20–200 USD; faceted stones 200–800 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 bertrandite treated, and how?
Untreated. The world's main beryllium ore at Spor Mountain, where the associated opalised fluorite is sold as Tiffany Stone. Faceted bertrandite is tiny and very rare.
Where does bertrandite come from?
Spor Mountain, Juab County, Utah, USA, Mount Antero, Chaffee County, Colorado, USA and Golconda, Minas Gerais, Brazil. Origin affects price, so we name the locality rather than the country on every quote.
Is bertrandite hard enough to wear every day?
With care. It is 6–7 on the Mohs scale, which is hard enough, but perfect in one direction cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does bertrandite cost?
Indicatively Specimens 20–200 USD; faceted stones 200–800 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 bertrandite confused with?
Most often Phenakite, Beryl, Danburite and Herderite. A refractive index of 1.583–1.614 and a specific gravity near 2.59–2.60 separate it quickly.
Related stones
Looking for bertrandite?
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 bertrandite