The facts
What rainbow Obsidian actually is
Mineralogically, rainbow Obsidian is volcanic glass — SiO₂-rich glass with oriented nanoinclusions, crystallising in the amorphous system.
The colour is caused by iridescent sheen from thin-film interference on aligned magnetite nanocrystal layers. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.48–1.51, and the specific gravity sits near 2.33–2.42; cleavage is none.
Where rainbow Obsidian comes from
The recognised sources are Jalisco, Mexico and Glass Butte, Oregon, 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 Obsidian is treated
Untreated. Getting the rainbow to show requires the cutter to orient the cabochon parallel to the nanocrystal layering, so cutting skill dominates value.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What rainbow Obsidian is confused with
The usual confusions are Golden sheen obsidian, Labradorite, Coated glass and Ammolite.
The separation is rarely a matter of opinion: refractive index 1.48–1.51 and specific gravity 2.33–2.42 settle most of it in a minute, and magnification settles the rest.
What rainbow Obsidian is used for
Rainbow Obsidian is bought by jewellery, carving and sculpture, decorative objects 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, by the block or by the piece.
Durability and care
Rainbow Obsidian is 5–5.5 on the Mohs scale, with none cleavage.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What rainbow Obsidian costs
Indicative pricing for rainbow Obsidian is $0.50–15/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 rainbow Obsidian treated, and how?
Untreated. Getting the rainbow to show requires the cutter to orient the cabochon parallel to the nanocrystal layering, so cutting skill dominates value.
Where does rainbow Obsidian come from?
Jalisco, Mexico and Glass Butte, Oregon, USA. Origin affects price, so we name the locality rather than the country on every quote.
Is rainbow Obsidian hard enough to wear every day?
Not really. At 5–5.5 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does rainbow Obsidian cost?
Indicatively $0.50–15/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 rainbow Obsidian confused with?
Most often Golden sheen obsidian, Labradorite, Coated glass and Ammolite. A refractive index of 1.48–1.51 and a specific gravity near 2.33–2.42 separate it quickly.
What is rainbow Obsidian used for besides jewellery?
carving and sculpture, decorative objects and mineral collecting. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for rainbow obsidian?
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 obsidian