CIBJO releases Gemmological Special Report: considers process of separating measurable facts from opinion; See Gemological Articles below.
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Sun Nov 17, 2019 6:06 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Mon Oct 01, 2018 9:32 am 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 833
Location: Mars PA
It is an old song, I think, but it sums up my feelings about showing bright, cyan colored tourmaline with that special glow like quality to innocent people. At times I feel like a film critic that can not enjoy the beauty of a movie because he has seen too many films. His experience forces him to compare and be critical, rather than just experience the moment. This post is all about the moment of discovery of beauty in paraiba type tourmaline.

Last week the skys over Mars, a small town north of Pittsburgh Pa, where I have lived for almost 40 years, were gray. I always walk a gemstone when I finish it, to begin getting to know its presence under different lighting conditions. Well my cutting has been breaked by both the lack of exciting tourmaline rough on the market and the lack of funds to a low level, so I did not have a new gem to walk. To fill the void I picked out an old friend from my collection. It was the first tourmaline, I finished, with such a strong presence that I knew something exceptional was coming out of Mozambique. (To see a picture of the gem and read more about its history, please visit my site, BruceFryTourmaline.com). If you search on the number 1088 you should find the post on the 3.36 carat emerald cut, easily.

This medium toned, highly saturated gem has the glow like quality that makes it really shine under darker, low light conditions. So when I stopped in at a local establishment to show it to a new friend, I knew I would get a good responce. And I did. She stopped her work and after spending more time to examine the gem than she really had too, wrapped her hand around the box to shield the gem from the light and began to ask me questions. Beauty had won another round of believing in the excellence of some tourmaline. (There is no color barrior to beauty in tourmaline in my opinion.) A retired engineer dropped in and had the gem trusted on him. After requesting vital information, another expression of surprise and amazement came out. I woke up my regular walking buddy, that I have shown other tourmaline to and received expressions of disbelief. Why people would think that manmade gems would be more beautiful than natural ones is a mystery to me.

This little trip brought home to me again, that paraiba rype tourmaline and its associates did not become highly desirerable because they are tourmaline. None of my friends had ever heard of tourmaline before I told them about it. It is not really the color either, though the people do like cyan. It is the whole nine yards, a natural gemstone with a wonderful color that is so exceptionally bright that it has a glow like quality.

It is my opinion that if that special copper bearing tourmaline you are considering buying does not have the whole 9 yards, it is not worth the high prices it is demanding. But if you can find a beauty, even if it has its faults (inclusions, native cut etc.), you will have the opportunity to climb on board a force that will continue to grow in value and always be rare. You might even be able to impress your friends.

Bruce


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Wed Oct 03, 2018 2:24 am 
Offline
Gemology Online Veteran

Joined: Thu Jan 03, 2008 3:48 pm
Posts: 689
Location: Vancouver, Canada
Hey Bruce - nice post!

A link to the stone in question (a stunner!) is here

https://www.brucefrytourmaline.com/wow-neon-cyan-cuprian-emerald-cut/

-Allan

_________________
Allan Aoyama
http://www.omnifaceter.net <- Omnifaceter is back online!


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Wed Oct 03, 2018 9:19 am 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 833
Location: Mars PA
A friend who was a goldsmith felt that it was the most beautiful stone in my collection. I traded it to him for a gold piece of jewelery before I realized that it contained copper. (I also expected to get more of it.) In fact copper as a chromophore had not yet been discovered in tourmaline from Mozambique. (Its discovery in a stone I had sent to the GIA is another story I detail on my site.) He had it sent to the GIA lab and rather expected a report like he gets about sapphire. Well they weighed it and measured it and said that is was a tourmaline as well as taking a picture. Then they made their stock statement that basically says, this variety of tourmaline is colored by copper and manganese and was named after Paraiba Brazil where it was originally discovered. It has since been found in other locations but it is acceptable in the trade to call it Paraiba.

With no mention of where the stone came from or whether it had been heated or not, my friend was not pleased with getting very little for his money. He actually call the GIA lab and expressed his displeasure. While he ended up with an agrement that the stone was beautiful, he got nothing more. The simple fact is that the labs can not determine if the tourmaline in question has had mild heat applied to it or not. And while a great deal of work has been done to build up libraries of chemical data on tourmaline with their associated discovery location there is still a significant chemical overlap between the limited number of discovery locations. ( You can now request a determination on location at a greater cost I believe. It can not always be provided.)

Fortunately for me, my friend needed cash quickly and I was able to buy it back before the price got too high. And while no stones is exceptional under all the lighting conditions we normally encounter, this stone wins the prize with the exception of a flood of bright direct sunlight. Now I have some Rubellites and Indicolites that are more than willing to grace the bright sunlight with great color and not leave the field of beauty uncontested to any other gemstone. (In my unbiased opinion of course.)

A final note. this stone's size at over 3 carats and the complete lack of any eye visible inclusions would put it outside the normal range of available material from Paraiba. It was probably heated, but that guess only comes from seeing pictures of the associated lot. It had a a very uniform appearence in color, tone and saturation. I have found that most of my unheated rough has more variation in color than the lot. Still I have never had any of my rough heated so I do not have an intimate view of the color changes in any of my stones.

Bruce


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Mon Oct 08, 2018 5:50 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Jan 31, 2006 12:38 pm
Posts: 889
Location: N.J.
I have a few "not so sure stones" in my collection. This tourmaline is one of them. Was purchased at a gem show many years ago from a Brazilian dealer. He claimed it was a copper bearing stone from the original mine and was asking quite a bit for it. I told him that since I don't know you and in my opinion it's not copper bearing that I could only pay what I would pay for a nice regular green toumaline . That would be 500 bucks for the 6ct. stone. My eyes see a medium tone slightly yellowish neon green. In real life the black shadows are not there. At some point it will go in for a report, but this one is not high on the list. He seemed a little insulted but still took my offer. Normally I only buy from dealers I know and trust, but on this one I rolled the dice.


Attachments:
Screenshot_20181008-174906_Gallery.jpg
Screenshot_20181008-174906_Gallery.jpg [ 1.14 MiB | Viewed 1117 times ]

_________________
Nick
Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Mon Oct 08, 2018 5:54 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Jan 31, 2006 12:38 pm
Posts: 889
Location: N.J.
Here's an old 9 ct. Purple Toumaline


Attachments:
Screenshot_20181008-175251_Gallery.jpg
Screenshot_20181008-175251_Gallery.jpg [ 1.33 MiB | Viewed 1117 times ]

_________________
Nick
Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Mon Oct 08, 2018 7:52 pm 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 833
Location: Mars PA
I have found more yellow green copper bearing tourmaline with my spectrometer than I ever bought as cuprian. I think that this color is brighter wih copper than without it, but the color can be the same as non cuprian. I have a yellow green that has copper, that I truly love. It weighs 6.03 carats (#148 on my site with picture) and has a light web of inclusions, but a moderate tone level that has that glow like presence. I did not buy it as cuprian (I bought it before copper was discovered in tourmaline from Mozambique) and the water warn pebble did not blow me away until I cut it. I did not feel that it was in the range of color blessed with the paraiba name, but a dealer with a lot more experience with the GIA is certain that it is green enough to be blessed. It is enough for me to prize it as one of my GEMS even though it is included and it is not for sale.

If you would like to pre screen your questionable tourmaline that may be cuprian, send them to me and I will run them for the cost of sending them back. The only color that I have problems with is pink/red because of a Mn+3 peak in the infrared and a limited spectrometer. I can certainly nail the yellow green, the same way the GIA does. (I also have problems with dark stones for lack of light) Finally the purple looks beautiful and I should not have problems with that color because it should have enough copper to see the infrared absorption of copper easily.

THE SPECTROMETER IS THE BEST WAY TO DETERMINE COPPER AS A CHROMOPHORE IN TOURMALINE.

Bruce


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Mon Oct 08, 2018 9:51 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19891
Location: San Francisco
I'm sure you've answered this before, Bruce.
What spectrometer are you using and can it be used on mounted gems?
Thanks.


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Tue Oct 09, 2018 12:54 am 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 833
Location: Mars PA
Hello,

My spectrometer is a StellarNet Black Comet It is limited by only going into the infrared to 851 nm and it should go further to be sure that manganese is not a problem. This is only a problem with pink/red tourmaline. StellarNet has a spectrometer with better infrared range and I would get it today. Check their catalogue on the inter net. Both units cost about the same, but my unit is linear accross the spectrometer while the greater range unit is not linear. I think the linearity may be useful for color work, but for just finding copper absorption peaks I don't think it is important.

The light is as important as the spectrometer. My light is their SL1 modfied to enhance it's blue end sensitivity.. It does not have useful levels of light below about 400nm even though the spectrometer can measure lower wave lengths. It is still useful for most gemstones that are not too dark. If I ever upgraded my system I would probably get a brighter light.

I think it can be used on gemstones that are set in jewelery as long as enough light is reflected back from the table. You just hold the light probe at about 45 degrees to the table and use a fiber that both emits light and returns lightback to the spectrometer. I have tested many gems this way.

The whole process of looking for absorption peaks needs some adjustments in the position of the light, but is really easy and quick when you get a little experience. It can really tell if the element in the analytical work is really a chromophore or may be just a surface contamination in the case of copper and tourmaline. The GIA test every tourmaline it thinks may have copper with a spectrometer (a bit more expensive than mine.)

Finally you do need a library of absorption graghs to know which elements produce which peaks. With tourmaline, as usual, it can be complex, but copper produces a clear indication of its effect and is lots of fun to find. It will also separate apatite from Paraiba and Rhodolite from Rubellite very easily. There are many more separations, but those two have been very useful for me.

Bruce


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Tue Oct 09, 2018 9:35 am 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Jan 31, 2006 12:38 pm
Posts: 889
Location: N.J.
Sounds good Bruce. PM me shipping info and I'll send you the green stone. All of my mounted stones were gifted away. Even though they reside in my safe I guess technically they are not mine. The purple toumaline was sold as a Rubellite. When I received it it didn't look like the pure red photoshopped stone on Kogan's website. The color was so nice I purchased 2 more. All mounted and given away. Here is a comparison of a stone that I consider Rubellite.


Attachments:
20181009_091457.jpg
20181009_091457.jpg [ 894.37 KiB | Viewed 1084 times ]

_________________
Nick
Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Tue Oct 09, 2018 10:03 am 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 833
Location: Mars PA
Pretty stones. There is a world of difference between reddish purples and bluish purples in the world of color in tourmaline, in my opinion. Bluish purples are in the rarest section of the color world while reddest purples are reasonably common. You could call your purple a Siberite if you wanted to.

It is rather sad to me that the most unique hues of color in cuprian (the blue purples) tourmaline are heated away to make the cyan color that is duplicated by iron. There are hues of reddish purple in cuprian that are possibly not duplicated by other chromophores, but it is dangerous to exclude that possibility in such a complicated stone.

Bruce


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Fri Oct 12, 2018 8:14 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Jan 31, 2006 12:38 pm
Posts: 889
Location: N.J.
Sent green stone to Bruce today. I don't have a real good feeling about that stone. I also sent a few copper bearing blues? Not the greatest color but at least I'm sure they are toumalines. I want to thank Bruce in advance for checking them out.


Attachments:
Screenshot_20181012-192949_Gallery.jpg
Screenshot_20181012-192949_Gallery.jpg [ 761.91 KiB | Viewed 1036 times ]

_________________
Nick
Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Sat Oct 13, 2018 8:05 am 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 833
Location: Mars PA
I purchased my spectrometer because I found the labs pricing prohibitive to the point of limiting my knowledge and appreciation of copper as a chromophore in my collection of tourmaline. I felt that my collection would be enhanced because of the conditions under which I purchased the most important parts of it. I was greatly rewarded, but I still hunger to investigate as wide a world of color in tourmaline as I can with my enhanced eyes. If, in helping to satisfy my hunger, I can help you, that is great. I personally think that it is more expensive to handle the gemstones and produce the certifications than it is to determine if the tourmaline has copper or not with a spectrometer.

I am sure that your realize the following, but I think it should be stated.

1, I am only one retired person that does not handle deadlines very well.

2, I have limitations on what tourmaline I can test, that have to do with tone and color.

3, Copper as a chromophore in tourmaline is very rare and if your tourmaline did not come from the right areas of the world, it is very unlikely that it is cuprian no matter what color it is.

4, My determination certainly has no weight in the market, but I can help someone from making an unfortunate purchases or incurring the cost of laboratory certification that has very limited usefulness.

Let the adventure continue.

Bruce


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Sat Oct 13, 2018 3:39 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Jan 31, 2006 12:38 pm
Posts: 889
Location: N.J.
Hi Bruce - No deadlines on my stones . Keep them as long as you wish, take a look at them in your spare time. I remember you mentioning that some blue Paraibas's have a slight grey undertone. This is the case on 3 of the 4 blues. Not sure if heating will drive off grey or not. Not looking for any kind of value- I feel the the stones are only worth what I paid, maybe less on the green stone. Again, thanks for your help, I really value your opinion on all things tourmaline.

_________________
Nick


Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Sat Oct 20, 2018 7:37 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Tue Jan 31, 2006 12:38 pm
Posts: 889
Location: N.J.
Bruce very kindly did a spectrometer reading on this lot of toumalines.He confirmed that the green was non-cuprian. All the blues with the exception of the small round were also colored by iron. Only the small round was Paraiba. Goes to show that collectors need to very careful when a dealer claims that what he is selling is Paraiba . Luckily for me I paid regular toumaline price. Thanks, Bruce.


Attachments:
Screenshot_20181020-110210_Photo Editor.jpg
Screenshot_20181020-110210_Photo Editor.jpg [ 934.72 KiB | Viewed 883 times ]

_________________
Nick
Top
 Profile  
Reply with quote  
 Post subject: Re: Walking my baby (paraiba type tourmaline) back home.
PostPosted: Mon Oct 22, 2018 11:53 am 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 833
Location: Mars PA
It was a pleasure to help.

And now I will take this moment to express a pet peeve. So called experts expound on tourmaline being either a "daylight" gem or a "night time" gem. Well with so many colors and tones to say all tourmaline gems look best in the day or night is just not so.

I could go into too many examples that I have written about on my site, but for this post I will focus on Paraiba blues in the sample of gems nicky sent me. Without a spectrometer available, please look at how the gems behave under different light sources. The blue green/cyan color should brighten considerable under lower intensity incandescent light if it is good quality. I have found that high light levels are overwhelm to most medium to low tone levels of tourmaline. Paraiba still loves daylight/bluer light, but to me it looks more like Aqua. At least in most of my medium toned gems. I don't think that iron based, medium toned tourmaline respond as strongly to yellowish/incandescent light, but we all have different eyes and mine are growing yellower with age. It is natural.

So don''t let experts/people tell you about the changes in the colors of tourmaline under different lights, (That includes me) go out there and SEE it. Then you will appreciate how dynamic its colors are. Nothing is simple in the world of tourmaline. Oh and the greens tend to be pretty stable except for the ones that really want to be blue. Some of them can shift/change quite strongly.

Bruce


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock