Good news in earlier today from Teófilo Otoni gem dealers exhibiting at the 2009 Hong Kong Gem Show

The news from Praça Tiradentes this morning is that so far sales have been good in Hong Kong for the Teófilo Otoni gem dealers.

What a break this is after lackluster sales earlier in Bangkok and at the FIPP2009.

As expected, the best movers were the larger, high-quality aquamarines, alexandrites, and tourmalines, in particular the indescribably beautiful mint green tourmalines from the Pirineo mines.

Among the sellers from Teófilo Otoni with stands in Hong Kong are: Oswaldo Tavares, Marcelo Gemas, Mamão, Duarte & Bastos, and Emerson Tavares. (Remember that Teófilo Otoni is a very small town, and the well known sellers may be recognized by only their first names.)

Stands in Hong Kong can cost US$8,000. Add to that the cost of flying and hotel rooms, and if these dealers are sending happy news, then they must really be pleased!

Copyright © 2009 N. Tenney Naumer -- All rights reserved.

What I wouldn't give for one of these beauties from Pirineo!

Photo by Anfilófio Bastos, 2009.

Gorgeous, enormous, and problematic green tourmalines in Teófilo Otoni

Let's talk about these two beauties.

The first one, at the top (or on the left, depending on how your browser displays this page), is actually green going into blue-green. It is a good 2 inches long. If you were to buy it for yourself, all well and good. But if you are buying it to resell, what to do? What types of clients do you have? For example, what is a jeweler going to do with such a long stone? Really, it is too long to put in a ring. Should it be set into a pendant? I dunno. A pendant would not really show off the beauty of this stone. What about a brooch? Do you have jeweler clients who specialize in making brooches? Hmmm. This leaves you with thinking about your clients who are collectors and who are not interested in setting this stone. It is a marvelous example of a flawless bicolor tourmaline that goes from green into blue-green.

OK, now let's have a look at the second stone on the right (or below). This beauty has even more problems than the first one. This stone is so large that it is next to impossible to set (if I remember correctly, it was somewhere between 40 and 60 carats). This leaves it for a collector. But look at the cut. Look at the table. Hellooo! Really nice window to the bottom, isn't it!

You could have the stone recut as a round, but it might still be way too large to put in a ring, unless you are willing to lose a lot of carat weight. And for that, you need to pay a low-enough per carat price, because basically we are talking about rough here now, aren't we?

This stone is a perfect example of the prevailing tendency (by the less sophisticated dealers) here in Brazil to cut the stone as large as possible. This is called to aproveitar the stone (or to "take advantage" of the stone). They will have the stone cut as large as possible while still avoiding inclusions. Some of the really unsophisticated sellers will have the stones cut even larger and include inclusions in the belief that size is more important than an obvious flaw.

Copyright © 2009 N. Tenney Naumer -- All rights reserved.

On Pink Tourmalines from Araçuaí, Minas Gerais -- To Heat or Not To Heat

The tourmaline mines around Araçuaí in Minas Gerais are aptly famous for their pink tourmalines, although they have great greens, as well.

Pink tourmalines from Araçuaí are routinely heated because they often have a strong underlying brown tone. You can see examples of unheated and heated in this image taken in a dealer's office in Teófilo Otoni in March this year (click on the image to see the entire photo):


Generally speaking, many of these pinks look very light and washed out in daylight, but at night, under incandescent light, they have a wonderful color shift and change to a brilliant cherry color, although the brownish tone doesn't ever seem to be totally eliminated by heating.

In 2007, I bought an 18-carat oval for my mother -- IF at 30x -- and I had a terrible time trying to photograph it. In fact, I did not succeed. It looked just horrible in daylight, but at night -- wow!

Here is my best shot after several desperate attempts to manipulate the colors using Microsoft's Picture Manager, and it comes nowhere near doing justice to that stone:


On that same trip to Teófilo Otoni, I bought a 15-carat, peachy-pink, trillion-cut tourmaline that has something extra special about it that I have not seen before or since. As best as I can describe it, it was neon. And talk about not being able to photograph the particular beauty of that stone! Goodness! But I sent a message to a client in Rio de Janeiro, and he bought it sight unseen. When he received it, he sent me an e-mail to say that his eyes had fallen of his head when he saw it. It is nice when you have clients like that because if the sale had been based on a photo and not on trust, no one in their right mind would ever have bought that stone.

Copyright © 2009 N. Tenney Naumer -- All rights reserved.

Imperial topaz, characteristics and description, from the Ouro Preto region of Minas Gerais, available in Teófilo Otoni

[Photo copyright of Anfilófio Bastos. Please click on the photo at left to see the full screen image in all its glory! Or, click on this text to go to a collection of photos of stunning examples of the finest imperial topaz from the region of Ouro Preto, Minas Gerais!]

Recently, on one of the gemology forums, there was a discussion of imperial topaz. I was pretty surprised by the confusion as to what exactly is an imperial topaz.

For one thing, no one mentioned that the internal structure of real imperial topaz is quite different from common topaz. I don't have the technical vocabulary to describe it, but I can tell you what it does.

First, imperial topaz comes only from Minas Gerais in the region near the city of Ouro Preto. Minas Gerais is a very large state, comprising an area about 50% larger than the state of California, just to give you an idea.

The crystals are usually quite small in comparison to common topaz.

Unlike common topaz, their internal structure contains many tiny fractures. Thus, while cutting and polishing an imperial topaz, great care must be taken or it will break. And, sometimes these fractures are large enough to permit the polishing material to enter. Very fine visible fractures are normal in imperial topaz. Such fine fractures visible only at 10x normally do not affect the value of the stone greatly, although of course a really clear stone is more valuable, much like a clear rubilite tourmaline.

As already mentioned above, the crystal's color will intensify when viewed through the c-axis.

But the main difference is something called in Portuguese brilho de fogo, or "brilliance of fire."

Imperial topaz has a special way of reflecting light that causes it to shimmer.

Anyone who has actually seen real imperial topaz of even moderate quality will have seen this shimmer. It is somewhat similar to a schiller effect, but it is much finer and is extremely difficult to photograph, although I have come close even with my little amateur cameras.

Imperial topaz is defined by these special small shimmering crystals with internal fractures, and so far as I know, the only region in the world where they are found is in Minas Gerais.

As to color: imperial topaz comes in colors from a weak pale yellow to a better gold, to slightly orange, to salmon, to sherry and on along this sort of spectrum -- but they are all imperial topazes.

The difference is in the prices that are paid for these colors.

Some are heated to become pinkish. Lavender is a highly desired but rare color.

Nowadays, some are irradiated, but this is usually discernible because the colors have an intensity and tone that are not natural.

Generally, imperial topaz cannot be cut in the same way as common topaz due to the breakage problem. Thus, there are traditional cuts specific for imperial topaz.

I have seen irradiated citrines and low-quality rubilites cut in these imperial topaz cuts and hawked as imperial topaz.

Five years ago or more, common topaz (slightly off white in color) from the Khatlang province of Pakistan was being irradiated, and this process produced a very strong coppery orange shimmer, which unfortunately faded over time. It was noticeable that the shimmer effect was not nearly so fine. Nevertheless, these stones were often quite pretty.

The producers of this irradiated topaz did not bother to have it cut in the traditional cutting styles of real imperial topaz.

Very often, the irradiation produced very easily discernible color zoning -- something I have never seen in real imperial topaz.

The color was usually an orange copper with grey and brown undertones. It was especially easy to see these undertones and the color zoning if one put the stone, table down, on a piece of white paper and looked through the pavilion.

Sizes could go up to 40-50 carats -- an almost unheard of size for real imperial topaz.

But the dead giveaway was the price.

Even the lowliest cut imperial topaz with a washed-out, orange-salmon color (VS) would cost $12-$15 per carat in Teófilo Otoni.

A great website for finding the technical data on minerals, and with many good photos of these minerals, is www.mindat.org

That site currently has over 50 photos of imperial topaz crystals of the various natural colors. The first, a light golden brandy in color, displays the typical size, shape, color, and form of the most commonly found imperial topaz crystal, not to mention the internal fractures. These crystals can be had for pennies, as they are not gem quality and are sold merely as curiosities. The descriptions of the imperial topaz crystals on mindat contain a lot of hype. Almost none of the brandy-colored crystals is gem quality. The lavender crystals, however, are valuable. Here is the link:

http://www.mindat.org/min-8110.html

Copyright © 2009 N. Tenney Naumer -- All rights reserved.

Here is a link to a flickr album with photos of variously colored imperial topazes cut and available at the firm of Duarte & Bastos in Teófilo Otoni (photos by Anfilófio Bastos):

http://www.flickr.com/photos/dbprecious/sets/72157622158501184/detail/