The facts
What fayalite actually is
Mineralogically, fayalite is olivine group — Fe₂SiO₄, crystallising in the orthorhombic system.
The colour is caused by fe²⁺ gives greenish yellow to amber brown. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.827–1.879, and the specific gravity sits near 4.39; cleavage is imperfect in two directions.
Where fayalite comes from
The recognised sources are Rockport, Massachusetts, USA, Obsidian Cliff, Yellowstone, Wyoming, USA and Pantelleria, Sicily, Italy.
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 fayalite is treated
Untreated. Facetable transparent crystals are very scarce and come mainly from rhyolite cavities; almost all commercial olivine gem material is magnesian peridot instead.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What fayalite is confused with
The usual confusions are Peridot, Sinhalite and Chrysoberyl.
The separation is rarely a matter of opinion: refractive index 1.827–1.879 and specific gravity 4.39 settle most of it in a minute, and magnification settles the rest.
What fayalite is used for
Fayalite is bought by 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 specimen.
Durability and care
Hardness 6.5–7; cleavage imperfect in two directions. 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 fayalite costs
Indicative pricing for fayalite is Faceted stones 60–300 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 fayalite treated, and how?
Untreated. Facetable transparent crystals are very scarce and come mainly from rhyolite cavities; almost all commercial olivine gem material is magnesian peridot instead.
Where does fayalite come from?
Rockport, Massachusetts, USA, Obsidian Cliff, Yellowstone, Wyoming, USA and Pantelleria, Sicily, Italy. Origin affects price, so we name the locality rather than the country on every quote.
Is fayalite hard enough to wear every day?
With care. It is 6.5–7 on the Mohs scale, which is hard enough, but imperfect in two directions cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does fayalite cost?
Indicatively Faceted stones 60–300 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 fayalite confused with?
Most often Peridot, Sinhalite and Chrysoberyl. A refractive index of 1.827–1.879 and a specific gravity near 4.39 separate it quickly.
Related stones
Looking for fayalite?
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 fayalite