The history of a purple/blue piece of rough and speculations.

What I will be posting today is just the beginning of an interesting tale of fail opportunities and hoped for successes.  To set the stage for this notable piece of rough, I have to give a brief run down of the history of cuprian tourmaline from Mozambique.  I have written about these steps in greater detail other places on the site so I will not digress too much I hope.

1,  Before 2000, I purchases a aquamarine like piece of tourmaline that, when cut, had a very bright neon look to it.  I continued to purchase as much as I could over the following years and felt that the gemstone could be cuprian.

2,  Around 2000,  I purchased my first piece of rough that had a strong reverse Alexandrite color change when cut into an oval.  I have since named this new variety of Elbaite, Laurellite.

3,   Over a year later, I purchased a piece of fine quality tourmaline that , when cut into an emerald cut, showed the strongest color change of any Laurellite.  It ended up being sent to the GIA, where it was both determined to be a strong color changer and the first tourmaline from Mozambique to be colored by copper and reported publicly.

4.  Up until the release of the GIA discovery of copper in tourmaline from Mozambique in the fall 2004 issue of Gems and Gemology, I was able to purchase some exceptional pieces of tourmaline rough that turned out later to be cuprian.  (The impact of the finding of cuprian tourmaline in Mozambique was still not generally appreciated until its presentation at a major gem show in 2006.

5,  Within a matter of months before the price of easily recognizable cuprian tourmaline rose significantly, I was able to purchase a world class piece of purple tourmaline.   The forty carat, eye clean, piece of rough had a vivid saturated purple that may not exist outside of tourmaline colored by copper and manganese.  This color is what I sought, when I purchased the rough that is the subject of this post.

6,  After I retired in 2007, I used some of my retirement money to purchase as many outstanding pieces of Mozambique tourmaline as I could, with a special focus on cuprian tourmaline.   I was during this time that I purchase a good sized nodule of tourmaline, that looked like the world class purple, but was only  cab grade.  Still I thought it had the color and I like to play with well colored tourmaline that are included, to get the best faceted stone I can cut.

7,  When I received the rough. which turned out to be a rather thin section of crystal that had broken off the mother perpendicular to the c axis.  It appeared to have a watermelon color distribution that was fascinating.  The central and thickest part of the rough remained purple under both incandescent and natural light, while the partial remains of the “rind” of the watermelon like distribution of color, changed color like Laurellite.

Since I had sent in the first cuprian tourmaline to the GIA, I had attempted to get more research done on Laurellite.  I got requests for rough that could be specially cut or dissolved to further the search for why Laurellite changes color.  I failed to renew generate much interest research interest except in a professor that I came to know because my younger daughter went to the university that worked at.  He needed a project for a student to work with a scanning electron microscope.  Making thin sections of part of the rough was the principle gain I would get out of the present research, but the professor was getting access to more sophisticated and useful instrumentation in the immediate future.

8,  Over a year later, I asked for the return of the rough and was rather aghast by how much material had been consumed by making the slice.  Still I had to remind myself that it had been cab grade and one of the rough principle problems was a crack down the middle of the piece.  So one side or the other would have to have been sacrificed to get acceptable stones.  So what was done was done, but the saddest part is that the slide was lost and no significant research work was ever done on it.

9,  So now it is probably about 2009 and I am pretty much dead in the water when it comes to research.  The professor still has some cuprian samples, but the “Great Recession” has helped clear the field of any research interest in Laurellite.  I continue on by purchasing a spectrometer and finding a number of cuprian tourmalines in the collection that were bought without knowing that they contained copper, as a chromophore, along with confirming that the world class purple contained copper.  (I also confirmed that all my major purchases of tourmaline that should have contained copper, did.

10,  Up until this morning, April 8, 2014,  I had squirreled away the rather munched “bicolor” nodule of cuprian tourmaline.  I swear, I even tried to loose it, but it still haunted me.  I had never really examined it closely to cut, because I wanted to have one piece of rough to help explain Laurellite.  It has become impossible for me to get comparable rough on the market, but I had cut a small emerald cut with half of it being Laurellite and the other half a stable purple.  This helped relieve some of the pressure on me to keep the rough uncut and I have hit bottom.  A bottom I thought I would never see, I have nothing in tourmaline either exciting or even worth cutting.  (Not completely true, but it makes a better story).  So I decided to seriously check out the rough and then I knew it was time to make the preforms.  Enough was enough, I had to see what I had been saving all those years.

The first serious look at the rough under incandescent had shown me that it was significantly different than the world class purple.  The c axis lost a great deal of its purple hue to blue, but still was distinctly purplish, while the a/b had completely lost its purple and was blue. (easily seen when I sliced the rough)  In the morning light the stone was purplish except for the bluish fringe that I had seen before.  (This certainly could have been effected by the mixing of the purplish c axis with the the a/b axis)  A dichroic cuprian tourmaline with a watermelon distribution that consists of a core of purple and a rind of Laurellite is a bit much.  But I was determined to move forward in cutting the rough to get the best gemstones I could get out of it.  And if science has interest in the gemstones, at some far distant time, that would be nice.  But more importantly to me, I would have created beauty from the rough before I die.

So I have a round and an oval that are nice ring sized preforms.  Their tone value is significantly reduced because I lost a lot of weight in trying to cut acceptable gemstones.  Even with my effort, they will be far from clean, but the material between the “naturals” is bright and with decent crystal, so the blue purple tourmalines should be nice.  Stay tuned for the continuing saga.  I will be cutting them soon.

And the cutting of the round is complete.  It weighs 1.62 carats and is a complex and interesting stone.  The purple color is concentrated in the center of the stone and is quite vibrant.  The amount of vibrant color in the center changes even under natural light because of it,s dichroic nature.  The yellowish twisted florescent replacement for an incandescent light has little effect on the color, but the old fashion incandescent turns the whole stone grayed blue.  It is definitely a distinct color changer and even though I have seen the change  often now, it is still amazing to see a purplish stone that is a warm tone in natural light turn a cool blue gray in incandescent that is rich in the red waves lengths of light.  I am looking forward to seeing the absorption curve for this new Laurellite, when it is compared with my world class purple that just get pinker in incandescent and other Laurellites.

As a foot note, there are certainly visible inclusions, but they are not really distracting to me.  And it has a very fine purple center for a tourmaline with  moderate tone level.

It will be a little while before I cut the oval since I just receive a new lot from Africa that is calling me.  All the pieces are included, so the challenge goes on.

 

 

Bruce

 

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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