The facts
What milarite actually is
Milarite is classified as milarite (osumilite group), with the composition (K,Na)Ca₂AlBe₂Si₁₂O₃₀·H₂O. It crystallises in the hexagonal, but anomalously biaxial and sectored with a uniaxial core system.
Colour comes from not documented — no source consulted gives a chromophore for its pale green, yellow and colourless range, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.529–1.551. Specific gravity around 2.46–2.61. Cleavage: imperfect {0001} and {1120}; brittle. Those three numbers separate it from most of what imitates it.
Where milarite comes from
Milarite is produced at Val Giuv, Tavetsch, Graubünden, Switzerland (the true original locality), José Pinto pegmatite, Jaguaraçu, Minas Gerais, Brazil, Rössing, Namibia and Valencia Mine, Guanajuato, Mexico.
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 milarite is treated
Untreated. A collector rarity whose facetable rough has come almost entirely from a single African source. The name honours 'Val Milar', which is a spurious type locality — the material actually came from Val Giuv. Weak chalky green fluorescence is reported.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What milarite is confused with
In the trade milarite is most often mistaken for, or substituted by, Beryl, Apatite, Quartz, Phenakite or Danburite.
The separation is rarely a matter of opinion: refractive index 1.529–1.551 and specific gravity 2.46–2.61 settle most of it in a minute, and magnification settles the rest.
What milarite is used for
Demand for milarite comes from mineral collecting, 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.
Durability and care
Hardness 5.5–6; cleavage imperfect {0001} and {1120}; brittle. 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 milarite costs
As a guide, milarite trades around $50–500/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 milarite treated, and how?
Untreated. A collector rarity whose facetable rough has come almost entirely from a single African source. The name honours 'Val Milar', which is a spurious type locality — the material actually came from Val Giuv. Weak chalky green fluorescence is reported.
Where does milarite come from?
Val Giuv, Tavetsch, Graubünden, Switzerland (the true original locality), José Pinto pegmatite, Jaguaraçu, Minas Gerais, Brazil, Rössing, Namibia and Valencia Mine, Guanajuato, Mexico. Origin affects price, so we name the locality rather than the country on every quote.
Is milarite hard enough to wear every day?
With care. It is 5.5–6 on the Mohs scale, which is hard enough, but imperfect {0001} and {1120}; brittle cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does milarite cost?
Indicatively $50–500/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 milarite confused with?
Most often Beryl, Apatite, Quartz, Phenakite and Danburite. A refractive index of 1.529–1.551 and a specific gravity near 2.46–2.61 separate it quickly.
Related stones
Looking for milarite?
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 milarite