In the not too distant past, we had read in trade related magazines that smaller Tanzanites ( normally be light in color due to size), were being coated to enhance their saturation. Though saddened to hear this, this was not of concern to us as the smaller and lighter material is common and readily available and not something we seek to stock. However, every time we hear of a new treatment, it puts a nail in the coffin for that particular gemstone and confuses the public. All That Glitters seeks out the rare and unusual in gemstones, and that is true when dealing in Tanzanite also. In the past, we have had the very fine richly colored Tanzanite, (some of this can be viewed on our Tanzanite page), as well as large (24.97ct certed) and uncommon colors such as Yellow, Green and Teal when it comes to Zoisite(when blue or purple, called Tanzanite).
During our travels in Thailand, we had made some purchases of richly colored blue to blue purple Tanzanites, with an exceptional one being a Trilliant of over 5cts. This piece was unusual because it glowed velvety blue-purple and reminded one of the internal glow of Kashmir Sapphire. This was the epitome of an extremely fine example of a natural and not often seen color in Tanzanite. This color is more common in larger pieces of say 10-20cts, but smaller gems of this color are far and few between. This was a keeper for All That Glitters inventory for these reasons.
Recently, while attending the 2010 Tucson Gem Show, there was a dealer with calibrated blue purple gemstones, very dark and rich, with several hundred available in all shapes. The color didn't quite look right, and I was thinking that this material was some type of synthetic. I asked the dealer what the material was - his response was, Tanzanite. My eyes opened wide and I exclaimed in dis-belief at first, Tanzanite!? This just didn't look right in color. The quantity was too large, the stones were quite dark but had color and life under bright lights, they were calibrated (normally material like this would not be calibrated due to loss in cutting) and the price was far lower than expected (Tanzanite is currently seeing a depressed price - so this fact is not surprising, but Tanzanite in this color and size would be considered perhaps too inexpensive).
At that time and with 30 years in the gemstone business dealing with Tanzanite rough and faceted gemstones in the past, for me to have to ask what a gemstone is at a show is not common. Some gemstones can be found in similar colors as other gemstones, such as Ruby, Sapphire and Spinel, and sometimes one has to ask for clarification and to differentiate. For my lack of recognizing "Tanzanite" says something right there....Are larger sized Tanzanite being treated with this coating, creating quite uniform coloration and a fine color that until recently was considered unique as in the case of our fine certed 5+ct trilliant? This is all too reminiscent of the Andesine Diffusion Enhancement that started a few years ago and shocked the trade when this enhancement was disclosed. Is this another variation? More and more enhancements are being performed on natural gemstones that it is hard to keep up. One dealer did note that as these processes continue, the truly natural gemstones go up in price.
With the facts discussed above, the only current 'natural' conclusion is that Tanzanite may be enhanced in any sizes, to improve their color. Anything new on the market, any new color for a gem species, any large quantity of any gemstone suddenly appearing on the market, now has to be questioned.
We know that in time, there will be more discussions on this issue. Stay tuned as others start to raise the same questions that the owner of All That Glitters has been contemplating.
As always, deal with those businesses you can trust. We not only offer a 7-day money back guarantee, but a LifeTime Guarantee on our gemstones. If we sell something as natural, indicate heat or other standard practices for some gemstones, and you discover a treatment not disclosed on the receipt, you can return the gemstone for a full refund regardless of time frame!