Paraiba/paraiba type tourmaline and treatments.

I have not seen a lot of finished Paraiba/paraiba type gemstones,  I have certainly cut a fair amount of different grades of rough.  I have also kept my ear to the ground and filled the air with questions.

Since I am sure that the gemstone that was described in the last comment came from Mozambique, I will start with a little history on the quality of cuprian material that has come from Mozambique.

Many colors have come from the Mozambique deposit, but the only clean material that came out at first was a dark rather dense purple red.  It came in rather larger sized pieces and could be partially heat treated to a lighter shade of lavender or completely changed to a pale blue to green color.  Some of the first cuprian material I got to cut was material like this.  All of it was water worn, so it was hard to see its purity and at least some of the material was sawed not cobbled.  While ending up rather pale, it has a wonderful color that I had not seen in tourmaline before.  I even sent my first stone back to my principle supplier in Africa to share the new color.

Along with the lavender explosion, I was getting really nicely colored rough that was generally smaller and included.  I was also able to purchase some exceptional pieces of rough at this time because I was willing to pay a good price for purple/blue purple material.  Now this was before copper was discovered in samples that I sent the GIA and purples like the kind copper/manganese produce in tourmaline are very rare.  Still purple was not yet a commercial color in tourmaline, so the prices were still moderate compared to great Rubellite/Indicolite etc.

When copper was discovered and announced in the reverse color changers I have come to call Laurellite  the prices of rough went much higher.   For a variety of reasons the level of clarity significantly decreased also.  I am sure that the heating of some of the rough to produce cyan material was part of the reason for the increase in flaws etc.  But I have no way if telling whether a tourmaline has been heated or not.  As I said earlier, having some residual purple in the gemstone does NOT guaranteed that is has not been heated.

Now what does the trade do with a significant amount of expensive and desirable material that can have its beauty enhance by a simple treatment?  They have been extensively using resin materials to hide inclusions after the material has been heated.  And I would say that only a small percentage of cuprian tourmaline from Mozambique comes in the desirable cyan color without heating.

So my guess is that the beautiful cyan colored tourmaline that you describe in your comment has been both heated to develop the color and treated with resin in enhance its clarity.  Seeing the “rainbow” effect is a dead give away that it has had clarity enhancement.   Not all cuprian tourmaline is enhanceable by heating, but greed can push people to endanger a beautiful gemstone by heating even if the gain in color maybe marginal.

Having said all that, I still can see your beautiful gemstone in my minds eye.  A rare and unique beauty that I would be pleased to own.

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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One Response to Paraiba/paraiba type tourmaline and treatments.

  1. David Walsh says:

    Hi Bruce!
    I have thoroughly enjoyed looking through your Tourmaline Gallery over the past year or so and have read through quite a few of your posts. I am a lover a Tourmaline as well. Most of my emphasis has been on collecting fine quality gems that have a blue color component. I have recently acquired a couple of parcels of what I believe to be copper-bearing rough from a reported new source in Nigeria. Me and my partner have already cut several beautiful, but smaller stones from the rough. I am writing today, because we are looking for advice in the testing/identification and heating arenas. On the heating side, we have begun with some preliminary testing of some small highly included pieces and have observed no real change. I have some photos of our rough and finished gems as well as additional details that I can email over to you. Our first parcel had a mix of color saturation. From a strong medium to a medium light and the material is clearly more blue than green. Most of the material in the first parcel was moderately to heavily included. Today we took delivery of a second parcel, including two larger, cleaner gems. One of the two seems like it would cut and excellent, large stone, except it is dark. On the heating side we are stuck. If you get a chance to chat with me via phone or email, it would be greatly appreciated! All the best, Dave … email: therareearthco@gmail.com … phone (757) 650-5720 … Thank you!

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