london blue topaz

[alma]

Where does this stone get it''s name? It''s quite a nice color--I assume they are mostly heat treated, aren''t they? What sort of quality stone is it, can anyone tell me?

 

[mike04456]

It's a trade name, meaning someone just thought it up for marketing purposes.

Virtually all blue topaz on the market is irradiated to produce the blue color. I like blue topaz, but there is so much available that it's dirt cheap these days--a couple of bucks a ct wholesale the last i checked.

 

[pyramid]

How much would a natural london blue topaz cost per carat which has not been heat treated or irradiated? Are there many available?

 

[Gemstudded]

Hi,
A natural untreated Blue Topaz is about $10/$15 per ct (Sky blue) from my last look (about 6 months ago). Unfortunately it's quite rare to find a natural Blue Topaz and as mentioned almost all are irradiated.
I would recommend collecting 10ct plus treated stones as a small investment. Personally I prefer the "Swiss Blue" variety, much richer dark blue and the most expensive of the blues

 

[gemexplorer]

Alma, I trust that the first round of irradiation via the so called "nuclear reactor" irradiation was done in London. Today they are now done in many places and we have treated topaz now from Sweden to University of Missouri.

The other process is in the use of Linear reactor to produce the light color like sky blue.

There is this combination of the two treatment to give the color of Swiss blue.

The topaz does come in a light blue but most of them are in white - the major exporter of the white topaz now is still Brazil from the Rondonia region (in the Amazons) and also from Nigeria. But India, China and many other nations do have white topaz.

I hope this information will help you a bit