The Tucson Gem and Mineral Show is a great place to see what's new from around the World. This year was a little disappointing for new gem discoveries as there was very little gem rough available. Demantoid garnet was available from Namibia, Madagascar and reports of a new discovery in California. I was told the California material has a high Chromium content with very deep green color and could be lightened by heating. This is the first time I have heard of effective heat treatment of garnet. Lapis was available in large quantities through out Tucson. In regards to treatments there are some disturbing reports of diffusion being done on tanzanite, garnet and blue zircon. I am not sure what type of diffusion is being done. Surface diffusion is easier to identify, while deep diffusion can penetrate the entire gem and is more difficult. I will be on top of this issue as it affects all who buy from unknown sources. It is rapidly becoming necessary to provide lab reports with every gem of value as treatments get more sofisticated. Opal from Ethiopia was available in both rough and cut gems and was selling well. Prices of cut Wello opal were up significantly for finer stones. Reports early in the show was that the government of Ethiopia was going to stop the export of opal rough to keep the cutting labor in Ethiopia. Just before leaving Tucson I heard from a reliable source that the law had passed. As an opal cutter and opal fanatic I hope it's not true. Fortunately I spent most of my money on the beautiful rough that was available. I met several Wello opal cutters in Tucson and the consensus was cutting Wello opal dry has less risks for cracking. I have been cutting wet and typically have one in 7-8 opals crack. Typically the break once down the middle and you can cut two smaller stones with no further risks of cracking. I have cut four opals so far with the dry method with no breakage. My only concern is once the gem is finished will the purchaser of the opal be at risk of breakage if they get the gem wet. I may soak the finished opal just to protect my customer from this disaster. Tanzanite prices were down although no one had an answer to why prices were so reasonable. I have lowered the prices of all larger tanzanites on We see this every few years and the rebound of prices is typically within a couple of months. I will get back to Tanzania soon to capitalize on these reduced prices. With the exception of tanzanite, fine gem prices were up dramatically. Strong buying from Asia, improved economy, environmental policies and general lack of production are causative factors for these steep rise in prices.

By Steve Moriarty