I have been motivated to make this post, by more than just ridiculous comments made about gemstones on the inter net. This does not mean that I don’t have a new pet peeve
about the inter net. The newest one is the declaration that Tanzanite is rarer than Paraiba tourmaline because it only comes from one location. I realize that the multiple sites that list the rarest most valuable gems and minerals etc. generally do not even mention Paraiba tourmaline, they still infer, by including Tanzanite, that Paraiba tourmaline does not make the grade. What a joke. In one of the larger crystals of Tanzanite there is probably more large clean top grade material than has ever been produced anywhere in the world, of Paraiba tourmaline.
Now that was a good motivator, but when a friend of mine began to construct a quick and dirty screening tool to see if there is a significant amount of copper in the rough he has and is buying, I think it is time to say something again and again. Copper in tourmaline in concentrations that make it a chromophore in tourmaline is a freak of nature. I realize that many of the older test methods either were destructive or limited in scope, so you needed to be looking for copper in the limited number of analysis that were done, to find it. But since the discovery of Paraiba tourmaline in Brazil, a great amount of effort has been made to fine more Paraiba/cuprian tourmaline with very limited success. This boils down to the fact that no matter how inexpensive and easy the copper test my friend is going to construct, the effort will bear little of interest, I am afraid.
After saying all that, I am still getting tourmaline rough from Mozambique that shows the effect of copper absorption. At least one larger, flaw piece was not sold to me as cuprian. But even with my spectrometer online the day of finding cuprian tourmaline is passing quickly. I wish it was not the case.
Bruce
