This is part of an “off-list” response that I sent to a subject that
had come up on the list. I think that others might be interested in
it.
when you mention that some of the stones such as the "special
care stones" are heat sensitive, up to what degrees Celsius can
they handle in temperature
I’ve never really measured the temperature, just watched what has
happened with jewelers who didn’t heed my or other’s warnings, -
like a large nice pink Kunzite in a shop window in the direct
sunlight for a long period which became completely colorless. Some
of the irradiated Blue Beryl can also have the color degrade. I
don’t know about the Irradiated Blue Fluorite - I have never dealt
with it.
So as a precaution, when I sell Blue Beryl, a paragraph of how to
care for the stone goes on the invoice. Basically - no steamer, no
torch, no heated ultrasonic, no prolonged periods in direct
sunlight.
Best regards Robert Lowe Lowe Associates - Brasil Gemstones, Rough,
Specimens Tucson February 6 - 11, 2003 - GJX # 205 e-mail: USA robertplowejr@juno.com e-mail: Brasil <@Robert_P_Lowe_Jr1>
On the subject of special care stones, I always thought that blue
topaz – which is both irradiated and heat treated, I believe – was
color-fast. Well, a necklace that I had strung with blue topaz beads
came back from consignment with nearly colorless beads! Am I wrong
in thinking that the treatments which create blue topaz are permanent
or do you think the beads I purchased were perhaps dyed and sold
fraudulently as blue topaz? Beth
Beth, I always wash my beads in a little dish soap and water before I
use them and repeatedly have had the blue topaz become colorless
leading me to believe that they were just dyed with some color on
the surface. I have bought them from different vendors with the
same results and, since I didn’t know where to get beads that didn’t
wash clear, have stopped using them. If anyone knows of better
quality topaz beads, I too would be interested.
Hi Beth… In the past, I have run across Topaz beads from India
(in necklace form) that have been “washed” with blue dye…in my
case this was disclosed by the seller…after a soak and scrub
(toothbrush) in warm soapy water they did lose some of their color,
but not a whole lot…
If your beads were dyed, display under hot lights/sunny window might
cause dye to fade…
I’m going to stick one of mine in a sunny window and see what
happens…
All, As more and more facetted stones are being subjected to
radioactivity and heat treatment you can expect to see a lot of
varying results. In blue topaz treatment the stability of the color
depends mainly upon two variables. One is the source of the topaz
and the second is the knowledge of the treater. There are a lot of
dealers selling blue topaz and some do not quality control their
process very well. Radiation of gemstones is now being done in
China, Vietnam, Brazil, India, Pakistan, USA, and Korea. All these
countries have different quality control and safety standards. I
probably missed a few, but these are the countries doing tonnage. As
far as I know there is no way to tell when you buy the stone that it
is color safe or radioactive free. In the USA there was at one time
a company that guaranteed their treatment results. I do not know the
name or if they are still in business. I get my blue topaz from a
dealer who now is out of business and selling off the last of his
stock. He radiated in the USA so his stones are radioactive free and
he guarantees the process as color safe. Be advised that I have seen
color fade in topaz, aquamarine, tanzanite, and kunzite. I have been
also told that amethyst is now being made from clear natural quartz.
It was reported from the Swiss Lab in JCK Magazine. Beware!
Hello Beth I have experienced that many treated stones cannot
tolerate long exposures to sunlight. Most of those seem to bleach out
to a clear or yucky color. Maybe your consignor had your necklace
displayed in a sunny window? I even know of Topaz (natural) from Utah
that loses its color in sunlight but if exposed long enough to neon
lights, like those found in jewellery cases, can turn pink again.
Karen Bahr “the Rocklady” (@Rocklady) K.I.S. Creations
May your gems always sparkle.
Beth, I believe that the common treatment for blue topaz is
radiation. I have used these stones for years without the problem
that you describe. Perhaps you are correct in your suspicions. Joel
Many stone beads on the market, especially blue topaz, are color
enhanced. The blue topaz stones often are a very pale blue (an
icy-white) without the addition of dyes. The first clue to
enhancement is the color of the temporary strand thread. The thread
color not only enhances the color of the stones but also hides the
fact that dye is used. Second, use a jeweler’s loupe to closely
view the stones. You usually can see where the die enters in
fissures, cracks, and chips and along the bead hole. The stone
tends to magnify even a small amount of dye. Third, dip one of the
beads in full strength household bleach, if you are still not sure.
If you bought the beads from a bead store (not a lapidary store),
the identification of the stones usually is lost in the retail mix.
Stone beads are in one section of the store and glass beads in
another. The clerks, and sometimes the buyer, identify the stone
beads by color only and these folks often do not know the codes for
natural, heat treated, or color enhanced (dyed). That is, all sky
blue transparent stones are called topaz. If you bought the beads
directly from a supplier, carefully read the descriptions and codes.
If enough is not provided, go elsewhere. I have always
liked Fire Mountain Gems, www.firemountaingems.com, because the
stone descriptions are very clear. And, they will refund your money
if you are unhappy with your order for any reason. Nancy www.psi-design.com