The facts
What chalcedony actually is
Mineralogically, chalcedony is chalcedony — SiO₂, crystallising in the trigonal system.
The colour is caused by varies; blue chalcedony from scattering and trace elements. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.530–1.540, and the specific gravity sits near 2.58–2.64; cleavage is none.
Where chalcedony comes from
The recognised sources are Namibia, Turkey, Indonesia, Malawi and Brazil.
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 chalcedony is treated
Dyeing widespread.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What chalcedony is confused with
The usual confusions are Dyed chalcedony, Larimar and Glass.
The separation is rarely a matter of opinion: refractive index 1.530–1.540 and specific gravity 2.58–2.64 settle most of it in a minute, and magnification settles the rest.
What chalcedony is used for
Chalcedony is bought by jewellery, carving and sculpture and decorative objects — 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
Chalcedony 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 chalcedony costs
Indicative pricing for chalcedony is $1–25/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 chalcedony treated, and how?
Dyeing widespread.
Where does chalcedony come from?
Namibia, Turkey, Indonesia, Malawi and Brazil. Origin affects price, so we name the locality rather than the country on every quote.
Is chalcedony 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 chalcedony cost?
Indicatively $1–25/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 chalcedony confused with?
Most often Dyed chalcedony, Larimar and Glass. A refractive index of 1.530–1.540 and a specific gravity near 2.58–2.64 separate it quickly.
What is chalcedony used for besides jewellery?
carving and sculpture and decorative objects. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for chalcedony?
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 chalcedony