I was put in my place last week regarding pink topaz when I
suggested it to someone looking for an inexpensive hot pink stone and
they weren't bothered about the colour being the result of some sort
of treatment. I was told that naturally pink topaz was very expensive
and that other pink topaz was the result of a surface treatment and
that such stones were junk.
I contacted my supplier regarding this and he contacted the
gemological lab from whom he buys his pink topaz stones. They assured
him that they do NOT deal in surface treated stones and that the pink
topaz they sell him is heat treated. It was also suggested to me last
week that I put my pink topaz gems into water and that the surface
treatment would show up. The only one that showed itself to be
surface treated was one that I bought from Thailand and it did indeed
appear to be a colourless topaz with a pink surface coating. However,
the pink topaz I bought from my UK supplier that he assured me were
heat treated were all indeed pink all the way through.
This link talks about pink topaz being the result of heat treatment
and that it's a permanent treatment. "Most pink topaz is obtained by
carefully heating brownish red-yellow chrome-bearing crystals found
at Ouro Preto in the Minas Gerais region. Although the color of some
natural crystals fades when exposed to sunlight, this heat-induced
color-change is permanent."
Again the above link states pink topaz being a permanent heat
treatment. "Orange-brown Topaz is heat treated to 450 C to bring out
a purplish-pink color (pinking). These treatments are permanent and
do not affect the stone's durability or hardness."
So who's correct, those who say that treated pink topaz is nothing
but surface coated junk, or those sources who say topaz can be heat
treated to produce a permanent pink colour? If my supplier and his
supplier are correct and the two sources I've cited above, then
perhaps people should be a little slower to chastise and belittle.
I'd be interested to hear from anyone else who happily uses heat
treated pink topaz and doesn't consider it junk or anybody who can
provide me with proof from reliable sources that heat treated pink
topaz doesn't exist.