Saturday, October 21, 2006

Mozambique Cuprian Tourmaline, Part III




Mozambique Cuprian Tourmaline, Part III


Purple Cuprian; A dilemma:

By Richard W. Wise, G.G.

©2006



“I know what you're thinking. Did he fire six shots or only five? Well, to tell you the truth, in all this excitement, I've kinda lost track myself. But being as this is a .44 Magnum, the most powerful handgun in the world, and would blow your head clean off, you've got to ask yourself one question: Do I feel lucky? Well, do ya punk?”


Clint Eastwood


As tourmaline aficianados know, there are few truly rare colors of tourmaline. A pure yellow without a stong green secondary hue is quite rare and I have never seen a true violet but until recently, purple was the one spectral color that absolutely did not exist in tourmaline. Yes we had purplish reds but until last year when the Alta Lighona tourmalines from Mozambique entered the market, never a stone with a purple primary hue. (pictured above: 15.5 carat purple Mozambique cuprian tourmaline courtesy Pala International)

In early 1989 when the first curpian tourmalines from Paraiba appeared in the market in Brazil some were sold unheated. Most of these stones were a dark toned greenish “sapphire” blue, a “Thai sapphire blue” to be precise. In those days, blue was the most expensive, elusive and sought after color in tourmaline. Rumors whispered of a pure blue gem that was reputed to rival the finest in Burmese sapphire. This was the holy grail of tourmaline. I recall holding on to one parcel of natural dark blue Pariaba for several years before I burned them just in case the demand for the medium electric blue proved to be a passing fancy. Well, as we know it did not and when I finally did heat it, the result was a half dozen pure medium toned visually pure Carrribean blue gems that I sold at a substantial profit.

Since that time I have seen many examples of blue tourmaline including the famous Manoel Mutuca (described by Proctor as “sapphire blue” see Gems & Gemology, Spring 1985, p.11)) and Santa Rosa material but none (at least so far) with a true pure blue hue. Blue tourmaline always has a distinct greenish secondary hue which becomes quite evident when it is compared stone to stone with fine sapphire. Blue tourmaline can be exceptionally beautiful but it looks like tourmaline not sapphire.


To burn or not to burn or "Do I feel lucky? Well, do ya punk?”


With the entry of Mozambique curprian tourmaline we have a dilemma similar to the situation with the early Brazilian curprian tourmaline namely that some of the unburned material has a rich pure purple hue that reminds one of Siberian amethyst or fine purple sapphire. The difference is that unlike the rather dull greenish blue unheated Paraiba, this stuff is beautiful,

The Mozambique purples have a hue that is rich and pure. So, to burn or not to burn, that is the question, according to both Gene Flanigan from Precision Gems and Josh Hall at Pala International, these deep purples are also the best candidates for the oven, they heat to a neon pure medium “Paraiba” blue.

Some dealers have chosen the obvious solution. If you want a pure purple but burnable stone they will charge the same price as for the neon blue.(pictured above: unheated cuprian rough from Mozambique). Pictured below is an exceptional 1.89 carat custom cut Carribean blue cuprian stone cut from the center piece of rough. After and before; the first image shows the cut stone before heating. The second image shows the stone after the heating process was completed. The stone, currently available for sale at www.rwwise.com was cut by Gene Flanigan a very talented lapidary artist from upstate New York. (Images courtesy Gene Flanigan: www.precisiongem.com)

Will purple tourmaline go the way of fine star sapphires that hardly exist anymore because they can be burned and faceted? I don't think so, some of the fine purples simply possess problematic inclusions that make them risky candidates for burning. I found an 8.19 carat oval, a lovely example of Mozambique purple on my last trip to Asia. This stone faces up clean but under magnification shows long growth tube inclusions and cannot be burned. It is out having its picture taken and will be posted in a later blog. Logically purple cuprian tourmaline will have a two track price structure. Stones with a high degree of clarity under the loupe will sell for prices that may be double that for stones with certain types of inclusions whether visible or not.

Bits and Pieces:

I get lots of emails. Don't think I'm not grateful. Every once in a while a real interesting one comes through the mailbox. take this on:

Position Available:

Dear Mr Wise,
We are Stargate, diamond trading division of Ebenhaezer Bank Consulting Group of Belgium, operating in thirty countries worldwide. We have read your blog regarding the appraisal of stones by qualified experts. We have constant need of qualified gemologists, expert in assessing ROUGH DIAMONDS, and have great difficulty identifying where they can be located.
We offer good working conditions, contracts, and a fair remuneration.
A special need has arisen in Bangui, Central African Republic, where we are currently (this week) accepting a large consignment. We require the services of a qualified gemologist, expert in rough diamonds, to assist our team there.
Would you be kind enough to assist us at your earliest convenience?

Yours sincerely,
Lucilla Arioti
Global Client Relationship Manager, EMEA
Stargate,
a division of Ebenhaezer Bank Consulting Group
Telephone: London +44 207 870 5389

I am not familiar with Stargate but believe the lady is serious. She even called and left a message on my machine. So if you are a gemologist in search of adventure give Lucilla a jingle. This time next month you could looking at sparklies and sipping pina colodas in beautiful downtown Bengui. As for myself I'd love to go along but I can't give up my day job but when you get there be sure to drop me a line and oh do
be sure to take along a flack jacket.

New Site with excellent online library of inclusions:

Got an email from a French gemologist:
Marie-France Boursier-Brard. Ms Boursier-Brard has developed an excellent site with online images of inclusions. The site is quite comprehensive and well organized. Just click on: www.gemmes-inclusions.com




Check out my book Secrets of The Gem Trade; The Connoisseurs guide To Precious Gemstones: www.secretsofthegemtrade.com.


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Editor-in-Chief Colored Stone Magazine




3 comments:

Simon Watt said...

Finally a discussion about Purple Tourmaline! When I first saw Paraiba Tourmaline, back in the eighties, in parcels of mixed colours, one of the colours was purple. The purple I am talking about was like the very finest blue tanzanite colour. The colour was fabulous, but it did not sell the same as the other colours of Paraiba. The reason for this was that the colour already existed in other gemstones, e.g: sapphire and tanzanite. Paraiba sold so well partly because it came in colours not ever seen before in any kind of gemstone and customers didn't even ask what the stones were. The fact that they were tourmalines was entirely secondary, it didn't matter because the colours sold themselves.
We ended up burning all the purple stones that we had. These of course turned in to the most valuable colour of Paraiba......Windex Blue!
This is the reason that "purple' paraiba has been non-existent since the early days of the find..........they were all burnt.
There is a cover of Gems & Gemology from about fifteen years ago that has a group of various different stones and one of them is a 15-20ct size "gem" tanzanite/colour Paraiba that I know was bought by a collector in Michigan.
The first Mozambique Cuprian Tourmaline we saw was in fact lilac in colour and we still have a pair of cushions that I will e-mail you a picture of. I will also e-mail you a picture of some Paraibe rough I have here that is an extraordinary blue.
Blog on!!!

POND'S flawless white™ said...

I have no problem with its original color.

Terri said...

I recently acquired a bi-color tourmaline from Mozambique that appears to be straw yellow and grass green when outdoors in the shade yet turns a vivid pink and blue when in direct sunlight. Indoors under fluorescent light it turns a paler pink and silver gray. It also shows distint and vivid pleiochroism when rotated. Can you provide any information about this color change?