The facts
What fire Agate actually is
Fire Agate is classified as chalcedony, with the composition SiO₂ + goethite/limonite platelets. It crystallises in the trigonal (cryptocrystalline) system.
Colour comes from iridescence from thin-film interference on layers of iron oxide (goethite) platelets beneath the silica surface, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.530–1.539. Specific gravity around 2.58–2.64. Cleavage: none. Those three numbers separate it from most of what imitates it.
Where fire Agate comes from
Fire Agate is produced at Deer Creek, Arizona, USA, Slaughter Mountain, Arizona, USA and Aguascalientes, 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 fire Agate is treated
Untreated. Value depends entirely on the cutter following the iridescent layer — a skilled free-form cut, not calibration. Assembled doublets over weak fire exist.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What fire Agate is confused with
In the trade fire Agate is most often mistaken for, or substituted by, Boulder opal, Ammolite or Assembled doublets.
The separation is rarely a matter of opinion: refractive index 1.530–1.539 and specific gravity 2.58–2.64 settle most of it in a minute, and magnification settles the rest.
What fire Agate is used for
Demand for fire Agate comes from jewellery, mineral collecting and decorative objects, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the carat, by the specimen or by the piece.
Durability and care
Hardness 6.5–7; cleavage none. That combination decides what it can safely be set into.
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 fire Agate costs
As a guide, fire Agate trades around $20–300/ct for strong multicolour fire.
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 Agate treated, and how?
Untreated. Value depends entirely on the cutter following the iridescent layer — a skilled free-form cut, not calibration. Assembled doublets over weak fire exist.
Where does fire Agate come from?
Deer Creek, Arizona, USA, Slaughter Mountain, Arizona, USA and Aguascalientes, Mexico. Origin affects price, so we name the locality rather than the country on every quote.
Is fire Agate 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 fire Agate cost?
Indicatively $20–300/ct for strong multicolour fire. 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 Agate confused with?
Most often Boulder opal, Ammolite and Assembled doublets. A refractive index of 1.530–1.539 and a specific gravity near 2.58–2.64 separate it quickly.
What is fire Agate used for besides jewellery?
mineral collecting and decorative objects. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for fire agate?
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 agate