The facts
What gem Silica actually is
The species behind gem Silica is chalcedony with chrysocolla inclusions, SiO₂ with Cu-bearing inclusions; it forms in the trigonal (cryptocrystalline) system.
Microscopic to submicroscopic chrysocolla inclusions, so the colour is from Cu²⁺ but not lattice-bound 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 1.530–1.543 and a specific gravity of about 2.55–2.70, with none cleavage.
Where gem Silica comes from
Commercial material comes from Ray Mine and Inspiration Mine, Globe–Miami district, Arizona, USA, Lily Mine, Ica, Peru, Acarí, Arequipa, Peru and Taiwan.
Different localities give different colour and different clarity, and the trade prices them differently. We state which one.
How gem Silica is treated
Untreated; the chalcedony host makes it far more durable than chrysocolla itself, which is the whole point of the material. The most expensive chalcedony in the trade. Dyed chalcedony and plastic are sold as gem silica, and the price gap makes that a real risk.
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 gem Silica is confused with
Watch for Chrysocolla, Turquoise, Dyed chalcedony, Amazonite and Blue opal — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.530–1.543 and specific gravity 2.55–2.70 settle most of it in a minute, and magnification settles the rest.
What gem Silica is used for
The trades that buy gem Silica are jewellery, carving and sculpture, decorative objects and mineral collecting. 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 block 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 gem Silica costs
Expect roughly $20–200/ct for fine translucent material, 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 gem Silica treated, and how?
Untreated; the chalcedony host makes it far more durable than chrysocolla itself, which is the whole point of the material. The most expensive chalcedony in the trade. Dyed chalcedony and plastic are sold as gem silica, and the price gap makes that a real risk.
Where does gem Silica come from?
Ray Mine and Inspiration Mine, Globe–Miami district, Arizona, USA, Lily Mine, Ica, Peru, Acarí, Arequipa, Peru and Taiwan. Origin affects price, so we name the locality rather than the country on every quote.
Is gem Silica 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 gem Silica cost?
Indicatively $20–200/ct for fine translucent material. 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 gem Silica confused with?
Most often Chrysocolla, Turquoise, Dyed chalcedony, Amazonite and Blue opal. A refractive index of 1.530–1.543 and a specific gravity near 2.55–2.70 separate it quickly.
What is gem Silica 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 gem silica?
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 gem silica