The amount of lead in tourmaline.

I have received data from the GIA on the tourmaline they ran on their laser ablation equipment during my latest trip to the west coast.  I have some questions, but one thing is obvious.  There is a lot more tourmaline with measurable amounts of lead than I thought.  When I first sumitted the reverse color changers (Laurellite) to the GIA for testing, they felt the lead they found was possibly from contamination during polishing.  It was later determined that many cuprian tourmaline have measurable lead.  Well now I have found some high levels of lead in non cuprian tourmaline.  One non cuprian purple, that is probably from Madagascar, had approximately 17,000 ppm which is higher than a colorless tourmaline that I thought exceptional.  (The achroite was tested at the Washington University of St Louis and its lead content was confirmed by GIA testing).

Both the purple and the colorless do not have significant amounts of copper and are Liddicoatites.  I do not know if having high levels of calcium has any impact on the levels of lead, but I feel they probably both came from Madacascar.

Ah the complexity of tourmaline.


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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