The facts
What rainbow Garnet actually is
Mineralogically, rainbow Garnet is garnet group (andradite) — Ca₃Fe₂(SiO₄)₃, crystallising in the isometric system.
The colour is caused by body colour from Fe³⁺; the spectral play is thin-film interference from lamellar growth layers just below the crystal surface. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.880–1.940, and the specific gravity sits near 3.80–3.90; cleavage is none.
Where rainbow Garnet comes from
The recognised sources are Tenkawa, Nara Prefecture, Japan, Sonora, Mexico and Sierra County, New Mexico, USA.
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 rainbow Garnet is treated
Untreated. The iridescence is a surface-parallel phenomenon, so the effect is destroyed by deep polishing — stones are cut to preserve the natural crystal face.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What rainbow Garnet is confused with
The usual confusions are Ammolite, Labradorite, Fire agate and Hematite.
The separation is rarely a matter of opinion: refractive index 1.880–1.940 and specific gravity 3.80–3.90 settle most of it in a minute, and magnification settles the rest.
What rainbow Garnet is used for
Rainbow Garnet is bought by jewellery and 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 carat or by the specimen.
Durability and care
Rainbow Garnet is 6.5–7 on the Mohs scale, with none cleavage.
With no cleavage plane to worry about, the practical limit is abrasion rather than breakage, and it takes daily wear well.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What rainbow Garnet costs
Indicative pricing for rainbow Garnet is 50–600 USD/ct for well-oriented Japanese material.
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 rainbow Garnet treated, and how?
Untreated. The iridescence is a surface-parallel phenomenon, so the effect is destroyed by deep polishing — stones are cut to preserve the natural crystal face.
Where does rainbow Garnet come from?
Tenkawa, Nara Prefecture, Japan, Sonora, Mexico and Sierra County, New Mexico, USA. Origin affects price, so we name the locality rather than the country on every quote.
Is rainbow Garnet hard enough to wear every day?
Yes. At 6.5–7 on the Mohs scale with no cleavage plane, it handles daily wear well. The practical limit is gradual abrasion rather than chipping.
How much does rainbow Garnet cost?
Indicatively 50–600 USD/ct for well-oriented Japanese material. 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 rainbow Garnet confused with?
Most often Ammolite, Labradorite, Fire agate and Hematite. A refractive index of 1.880–1.940 and a specific gravity near 3.80–3.90 separate it quickly.
Related stones
Looking for rainbow garnet?
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 rainbow garnet