Purple and heated cuprian/paraiba tourmaline

There seems to be a universal acceptance that if a cuprian/paraiba tourmaline has a purplish cast/overtone it is unheated. This not true. At least early on the exploitation of the Mozambique deposit,, large highly toned red/purple nodules were found. They were so dark that they were heated to make lavender colored gems. The change in color/tone level took hours of heating and could be haulted at any stage in the change. This was before anyone realized that they contained copper and might be of more value if heated to their ultimate very pale blue color.. There was some variability in the end product produced by the prolong heating, with at least one supperior green gem being produced that I know of.

Whether a cuprian tourmaline is heated or not is not critical to its value/beauty, but sellers like to make a point about knowing if the gemstone was heated or not. Sort of like the big deal made out of heated or unheated corundum. No lab will certify that a tourmaline has or has not been heated yet. They are working on it.

Bruce

About Bruce Fry

I was born in Summit, NJ in 1947 and graduated from Summit High School in 1966. I graduated from the Colorado School of Mines in 1970 and after spending another year in graduate school, I left to see the world of Brazil. After spending some more time discovering myself, I ended up working for the Commonwealth of Pennsylvania for 32 years as an Air Quality Engineer in the Department of Environmental Protection. I retired in 2007 and took up faceting gemstones again after a long hiatus that reached back to my twenties. I had started cutting cabochons when I was 13 and bought my first faceting machine when I was 15, but ran out of money and time until I retired. My great love in gemology is tourmaline and the collection presented here represents my effort to get as much beauty and variety in the colors of tourmaline as I can. I was particularly lucky in being able to get unheated cuprian tourmaline before copper was discovered in gem grade tourmaline from Mozambique.
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