I just finished a pin in which I used a stone that I now find myself
wondering about. It was sold to me as a red topaz. Does topaz
actually come in red? It was not at all expensive, but is quite
pretty. I just don’t want to mislead anybody when I go to sell it.
–Noel
Noel,
Yes, topaz is found in various reddish hues . If it was, as you say,
really inexpensive though, I would be suspicious. Rio Grande
citrine, for example, is found in hues similar to much more
expensive topaz. A quick refractive index reading would separate
those two however. There are other possibilities as well of course.
If you are not sure of the ID, maybe you could just say “pretty red
stone” and price it accordingly, eh? 
Jerry in Kodiak
It’s called rubilite…
Ringman
I would place a bet that it has either been heated, irradiated, or
diffusion treated.
Take a look at the corner meets with a microscope and see if the
color is inconsistant.
Craig
www.creativecutgems.com
Noel,
Red topaz is possible, but improbable. Heat treatment and
irradiation can bring about the red coloration, otherwise, red topaz
is improbable
In todays market almost any coloration is possible because of the
diversity of treatment.
Any deviation from the known natural colors of gems should be
treated with suspicion. Regrettably, we are fast approaching an era
in which appreciation of natural gemstones and their naturally
occuring attributes is no longer relevant or valued.
Ron Mills, Mills Gem Co, Los Osos, Ca.
I just finished a pin in which I used a stone that I now find myself wondering about. It was sold to me as a red topaz. Does topaz actually come in red? It was not at all expensive, but is quite pretty. I just don't want to mislead anybody when I go to sell it.
Topaz does occur in red, but it is usually quite expensive. Either
you got a good deal on it, or it’s something else. I’m tempted to
believe that the lemon “topaz” that was mentioned in another thread
was actually citrine (which may have previously been amethyst, but
heated to yellow). Gemological testing will tell you.
James in SoFl
OOps:
Wasn’t thinking, have seen one sample of red topaz, very small
piece, but was thinking watermelons! lmao ringman
I’ve seen some recently that was coated.
A word of caution. The stuff that I was looking at had what I
believe was a type of coating used to color eyeglasses. Not very
durable. Polished right off under tripoli. May as well have been
colored with a Sharpy.
Bruce D. Holmgrain
Goldwerx
http://www.goldwerx.com
@Red_Rodder
JA Certified Master Benchjeweler, CAD/CAM Services
I would place a bet that it has either been heated, irradiated, or diffusion treated. Take a look at the corner meets with a microscope and see if the color is inconsistant.
Unfortunately, I don’t have a microscope, but maybe I could borrow
one. Could you explain what you mean a little more? Where am I
looking, and for what?
–Noel
Well folks, my face is red, but that topaz-- isn’t!
Bruce Homgrain had it absolutely right. My “red topaz” has a coating
on it. Now that it is set (in 22k), the tip of the culet is not red
any more. I will have to take the stone out, and hope I can find
another that will fit. Or hold the piece until my faceting skills
are equal to cutting a stone to fit… (like that will be any time
soon!)
I confess I get a little consolation from not being alone-- Bruce,
you said the coating polished right off with Zam, so you (or your
customer?) must have fallen for the same deceptive practice. Man, it
really is caveat emptor out there!
Darn, and it was so pretty…
Well, the gem show is coming up in three weeks.
Noel (feeling foolish in suddenly-warm Chicago)
Oh-- and Happy Mother’s Day to all you muthas out there!
I would place a bet that it has either been heated, irradiated, or diffusion treated. Take a look at the corner meets with a microscope and see if the color is inconsistant.
Unfortunately, I don't have a microscope, but maybe I could borrow one. Could you explain what you mean a little more? Where am I looking, and for what?
Noel, perhaps the best way to do this is to first find a shallow
glass dish or, better yet, a shallow, white plastic (or Tupperware)
dish that will fit on the stage of the microscope. Basically, you’ll
be using it as an immersion cell similar to the one found at this
URL:
http://www.yourgemologist.com/immersion/cell.html
You must diffuse the light from the base of the microscope, so use
white plastic, or place a sheet of white paper under the clear glass
cell.
You probably don’t have methylene iodide to immerse your stone into,
but water will work well enough. Baby oil will work better as it’s
refractive index is closer to that of topaz. Put the stone in the
immersion cell, cover it with the liquid of your choice and place it
under the microscope. Hopefully, you’ll be able to see through most
of the stone even though it is mounted (I believe you did say you
had mounted it as a jewelry piece).
If it has been diffusion treated (I’m not sure anyone has ever
diffusion treated topaz, but that is what was suggested), you’ll see
the color of the stone has concentrated along the facet junctions.
Or possibly around the rim of the outline of the stone, or mainly
the center of it. Typically, untreated stones will be uniform in
their depth of color under immersion, while diffusion treated stones
tend to have their color concentrated in the center or along facet
junctions when viewed under immersion.
Best,
James in SoFl
Unfortunately, I don't have a microscope, but maybe I could borrow one. Could you explain what you mean a little more? Where am I looking, and for what?
If the stone was diffusion treated look for concentrations of color
when turning the stone in the light. Meaning, some facets or parts
of facets will seem darker. Also, under a 20x loupe (even 10x
sometimes) you may see small fractures which is an indication of high
temp’s. Also, look at the meets on the girdle to see if the color is
even and consistant. You are looking for areas near the corners and
edges that don’t have as much color, or the color looks like it
rubbed off.
A sure test is to scratch a facet and see if the color comes off.
Diffusion only touches a thin outer layer. Most teal, blue/green,
red, yellow, and ‘mystic’ topaz’s have this thin outer layer.
I hate to be negative but it would be highly unlikely that it is
natural, especially if it’s a ruby type red or ‘deep’ red. Almost
all topaz starts as white and is either heated, irradiated, or
diffusion treated (or all of the above).
Good luck,
Craig
www.creativecutgems.com
Diffusion treatment of topaz was patented in 1997-1998 (somewhere
around there). They’ve been doing it for a long time to create deep
blue, light blue, teal green, yellow, red, and numerous other
colors. The basic ingredient is the ever plentiful white topaz.
Craig
www.creativecutgems.com
I confess I get a little consolation from not being alone-- Bruce,
you said the coating polished right off with Zam, so you (or your
customer?) must have fallen for the same deceptive practice. Man, it
really is caveat emptor out there!
My boy Bob used to “Caviar enema!”
I really think that it came off with red rouge.
Fortunately my client understood who had ho-axed her …
Bruce Homgrain had it absolutely right. My "red topaz" has a coating on it. Now that it is set (in 22k), the tip of the culet is not red any more. I will have to take the stone out, and hope I can find another that will fit. Or hold the piece until my faceting skills are equal to cutting a stone to fit... (like that will be any time soon!)
Call RS Importing in New York 212-719-0087. They carry these coated
topaz stones and can answer your questions about the process used to
coat them. Most companies that deal with coated stones disclose it.
Secondary or tertiary people may not.
You will never be able to cut a coated stone without losing the
coating.
Eugene C. Gentile (Gino)
National Accounts Manager
Hoover & Strong, Inc.
877-687-7770
Fax: 609-936-1838
EGentile@hooverandstrong.com
Call RS Importing in New York 212-719-0087. They carry these coated topaz stones and can answer your questions about the process used to coat them.
Thanks, Eugene, but I don’t want anything to do with any more of
these coated stones, and I definately don’t want to cut, or recut,
any coated stones! I just want to try to make sure I don’t make the
mistake of buying any more of them, if I can.
–Noel
I don't want anything to do with any more of these coated stones, and I definately don't want to cut, or recut, any coated stones!
Noel, I totally understand! You cannot recoat them in your shop,
only replace them. The process is very complicated, patented, an only
done in one or two places. They are best to be avoided, but if your
customer insisted on having the same stone, I thought you would like
a resource.
Eugene C. Gentile (Gino)
National Accounts Manager
Hoover & Strong, Inc.
EGentile@hooverandstrong.com
