The facts
What cat's Eye Opal actually is
Cat's Eye Opal is classified as common or precious opal, with the composition SiO₂·nH₂O. It crystallises in the amorphous system.
Colour comes from body colour from iron or nickel; the eye comes from parallel fibrous structures or oriented inclusions in the opal, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.43–1.47. Specific gravity around 1.95–2.20. Cleavage: none. Those three numbers separate it from most of what imitates it.
Where cat's Eye Opal comes from
Cat's Eye Opal is produced at Ihosy, Ihorombe, Madagascar, Acarí, Arequipa, Peru and Tintenbar, New South Wales, Australia.
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 cat's Eye Opal is treated
Untreated, but hydrous opal can craze, so avoid heat and dry storage. A genuine but uncommon phenomenal variety; the eye is usually soft-edged rather than the sharp line seen in chrysoberyl.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What cat's Eye Opal is confused with
In the trade cat's Eye Opal is most often mistaken for, or substituted by, Cat's eye chrysoberyl, Cat's eye quartz or Satin spar.
The separation is rarely a matter of opinion: refractive index 1.43–1.47 and specific gravity 1.95–2.20 settle most of it in a minute, and magnification settles the rest.
What cat's Eye Opal is used for
Demand for cat's Eye Opal comes from jewellery and mineral collecting, 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 or by the specimen.
Durability and care
Cat's Eye Opal is 5.5–6.5 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 cat's Eye Opal costs
As a guide, cat's Eye Opal trades around 20–200 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 cat's Eye Opal treated, and how?
Untreated, but hydrous opal can craze, so avoid heat and dry storage. A genuine but uncommon phenomenal variety; the eye is usually soft-edged rather than the sharp line seen in chrysoberyl.
Where does cat's Eye Opal come from?
Ihosy, Ihorombe, Madagascar, Acarí, Arequipa, Peru and Tintenbar, New South Wales, Australia. Origin affects price, so we name the locality rather than the country on every quote.
Is cat's Eye Opal hard enough to wear every day?
Yes. At 5.5–6.5 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 cat's Eye Opal cost?
Indicatively 20–200 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 cat's Eye Opal confused with?
Most often Cat's eye chrysoberyl, Cat's eye quartz and Satin spar. A refractive index of 1.43–1.47 and a specific gravity near 1.95–2.20 separate it quickly.
Related stones
Looking for cat's eye opal?
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 cat's eye opal