The facts
What blue Topaz actually is
The species behind blue Topaz is topaz, Al₂SiO₄(F,OH)₂; it forms in the orthorhombic system.
Radiation-induced colour centre; natural blue topaz exists but is pale and scarce 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 1.609–1.617 and a specific gravity of about 3.53–3.59, with perfect basal {001} cleavage.
Where blue Topaz comes from
Commercial material comes from Minas Gerais, Brazil, Ouro Preto, Brazil, Nigeria and Ukraine.
Different localities give different colour and different clarity, and the trade prices them differently. We state which one.
How blue Topaz is treated
Essentially all of it is irradiated colourless topaz, then annealed. Neutron-irradiated material becomes residually radioactive and must be held in quarantine until it decays to legal limits — in the USA this is regulated by the NRC and irradiating facilities must be licensed. The treatment is permanent, undetectable by gemmological testing, and the reason blue topaz is one of the cheapest gems on the market. 'Swiss' and 'London' are colour grades, not origins.
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 blue Topaz is confused with
Watch for Aquamarine, Blue zircon, Blue glass, Synthetic spinel and Apatite — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.609–1.617 and specific gravity 3.53–3.59 settle most of it in a minute, and magnification settles the rest.
What blue Topaz is used for
The trades that buy blue Topaz 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
Hardness 8; cleavage perfect basal {001}. That combination decides what it can safely be set into.
Hardness is not the whole story. Perfect cleavage means the stone can split cleanly if struck along the wrong plane, whatever its Mohs number, so a protective setting matters more here than the hardness suggests.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What blue Topaz costs
Expect roughly $1–10/ct, 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 blue Topaz treated, and how?
Essentially all of it is irradiated colourless topaz, then annealed. Neutron-irradiated material becomes residually radioactive and must be held in quarantine until it decays to legal limits — in the USA this is regulated by the NRC and irradiating facilities must be licensed. The treatment is permanent, undetectable by gemmological testing, and the reason blue topaz is one of the cheapest gems on the market. 'Swiss' and 'London' are colour grades, not origins.
Where does blue Topaz come from?
Minas Gerais, Brazil, Ouro Preto, Brazil, Nigeria and Ukraine. Origin affects price, so we name the locality rather than the country on every quote.
Is blue Topaz hard enough to wear every day?
With care. It is 8 on the Mohs scale, which is hard enough, but perfect basal {001} cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does blue Topaz cost?
Indicatively $1–10/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 blue Topaz confused with?
Most often Aquamarine, Blue zircon, Blue glass, Synthetic spinel and Apatite. A refractive index of 1.609–1.617 and a specific gravity near 3.53–3.59 separate it quickly.
What is blue Topaz 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 blue topaz?
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 blue topaz