The facts
What fire Obsidian actually is
The species behind fire Obsidian is obsidian containing extremely thin, regular layers of magnetite nanocrystals that act as an optical thin-film stack, Rhyolitic glass with nanolayered magnetite Fe3O4; it forms in the amorphous system.
Thin-film interference from magnetite nanolayers approx. 200 nm thick, giving intense green, gold, magenta and blue is responsible for the colour — and the chromophore, not the name, is what decides whether a colour is stable.
On the instruments it reads a refractive index of 1.48-1.51 and a specific gravity of about 2.35-2.50, with none cleavage.
Where fire Obsidian comes from
Commercial material comes from Glass Buttes, Lake County, Oregon, USA - essentially the only known commercial source.
That is the whole list. A single source makes supply fragile and makes any claim of a second origin worth questioning.
How fire Obsidian is treated
Untreated, but the cutting is decisive: the thin-film layer is only microns thick and a cutter can destroy the effect in one pass, so labour is most of the value. Supply is limited to a small area on public land in Oregon with collecting-quantity limits. Widely imitated with coated glass and 'aura' treatments. Not CITES.
We state the treatment on every stone, including when the honest answer is that it cannot be determined. A treatment disclosed is a fact; a treatment discovered later is a refund.
What fire Obsidian is confused with
Watch for Coated and dichroic glass, Aura-treated quartz and obsidian, Rainbow obsidian (broader, less saturated bands) and Ammolite — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.48-1.51 and specific gravity 2.35-2.50 settle most of it in a minute, and magnification settles the rest.
What fire Obsidian is used for
The trades that buy fire Obsidian are jewellery, mineral collecting and carving and sculpture. They do not want the same thing, and they do not pay in the same unit.
We quote each application in the unit that trade actually buys in, by the carat, by the specimen or by the block.
Durability and care
Fire 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 fire Obsidian costs
Expect roughly $20-200 per cabochon; fine large well-oriented pieces $300-2,000, depending on quality.
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 fire Obsidian treated, and how?
Untreated, but the cutting is decisive: the thin-film layer is only microns thick and a cutter can destroy the effect in one pass, so labour is most of the value. Supply is limited to a small area on public land in Oregon with collecting-quantity limits. Widely imitated with coated glass and 'aura' treatments. Not CITES.
Where does fire Obsidian come from?
Glass Buttes, Lake County, Oregon, USA - essentially the only known commercial source. That is the only commercial source.
Is fire 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 fire Obsidian cost?
Indicatively $20-200 per cabochon; fine large well-oriented pieces $300-2,000. 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 fire Obsidian confused with?
Most often Coated and dichroic glass, Aura-treated quartz and obsidian, Rainbow obsidian (broader, less saturated bands) and Ammolite. A refractive index of 1.48-1.51 and a specific gravity near 2.35-2.50 separate it quickly.
What is fire Obsidian used for besides jewellery?
mineral collecting and carving and sculpture. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for fire 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 fire obsidian