paraiba tourmaline

[kathy]

This is my first day on this web site and I am not a gemologist. I have a stone whose picture I will post when I figure out how to do it. It is a pool blue tourmaline from mozambique, R.I. 1.64 and is doubly refractive. Is has some natural looking inclusions, no cureved striae or gas bubbles. What I want to know is are there any other tourmalines other than Paraibas this color? It does have some inclusions which could be copper. I want to be fairly sure before I send it for certification because of the cost.

[Jason]

Hi, the short answer to your question is yes, there are tourmalines colored by iron that are dead ringers for Paraiba type tourmaline. The only way to be sure if yours is colored by copper is to send it to a lab. If the stone is just a few carats I'd recommend sending it to AGL for the Fast Track report which is 55.00 and will tell you if the stone is a paraiba type. Good luck!

Jason

[roshanravan]

This is my first day on this web site and I am not a gemologist.

It is a pool blue tourmaline from mozambique, R.I. 1.64 and is doubly refractive

how did you got those results then? and how do you know the origin?

A paraíba tourmaline is a blue (electric blue, neon blue, violet blue), bluish green to greenish blue or green elbaite tourmaline, of medium to high saturation and tone (relative to this variety of tourmaline), mainly due to the presence of copper (Cu) and manganese (Mn) of whatever geographical origin.

you need to send it to an accredit Lab (as jason said) like AGL or GIA to make sure its elbaite tourmaline containing copper (Cu) and manganese (Mn)

[kathy]

[anitame]

Could be an apatite, too...

[Barbra Voltaire, FGG]

Quite right.
Any way to get a reading on the birefringence?

[kathy]

When I was just checking just the RI it said 1.63 and a half. When I checked for double refraction it went to almost the 1.64 line. I apologise if I am not phrasing things quite right. I am a beginner at this. Thank you for your input.

[Alberto]

hi,

have a look here: http://www.gemologyproject.com/wiki/ind ... ractometer
test the stone again and report
ciao
alberto

[Barbra Voltaire, FGG]

Yes...make sure you are properly testing for birefringence by rotating the stone and utilizing a polarized plate and a sodium light source.

[kathy]

Thank you for help on testing for bifingence, and now I realise that my pretty Apatite was sold to me under false information. Thankfully I didn't pay much. Hopefully learned my lesson. The bifringence was only 0.003 while my other tourmalines are 0.018. I assume all tourmalines have the same measurement?

[TRH2011]

Just from the photo it looks like apatite to me.

Oops, thats what I get for not reading the whole thread. looks like it is!

[Bill Hanneman]

The only way to be sure if yours is colored by copper is to send it to a lab. ... I'd recommend sending it ... for the Fast Track report which is 55.00 and will tell you if the stone is a paraiba type. Good luck!

Good advise, if one has only one stone. However, if you have many more, the most cost effective way is to purchase my Paraiba Picker and you can screen them for less than one cent each. Think of the postage and time you can save—besides owning a relative reflectometer which can instantly characterize your OTL gems. Only $99 plus $10 shipping to US, ($10 elsewhere).

I have resurfaced and I now have a mailing address:
W. Hanneman 264 Soledad Drive, Monterey, CA 93940
Anyone wanting more info on instruments available, please send an SASE. Thanks.

[bruce_tourm]

I have been screening many tourmaline for copper with my spectrometer and it is both very fast and a straight forward test, but without a certification from a quality gemological laboratory the value of the gemstone has probably not been increased much. I think, to just qualitatively determine copper in tourmaline should not be very expensive, but the handling of the gemstone in a laboratory is probably the biggest cost. I doubt that they are seeing much of it to process. Not much is coming out of anywhere now and an infrequent request will always be expensive to handle.

The one thing that my screening test will do for you, is tell you which gemstones are certainly not worth sending to a laboratory. When I decide to sell or heat some of my cuprian tourmaline, I will be guided by the testing to pick likely canidates to spend money on.

Bruce