AGTA GemFair Tucson, February 2011
After decreasing numbers of visitors in the past years it appears that Tucson is slowly recovering. However, the freezing temperatures during the week kept traffic low in the tents with the exception of the GJX which was busy. Apart from ubiquous Ethiopian opal and some impressive rhodochrosite crystals (Emperor and Empress of China) there was little else newsworthy.
Many friends and colleagues dropped by at the C.I.G. booth to check out the GL Gem Spectrometer.
Dr. Bill Hanneman’s new book “Pragmatic Spectroscopy for Gemologists” was ready and sold out quickly.
Renee Newman also visited our booth and presented her second volume of “Exotic Gems”- just ready for the Tucson gem shows.
The above books can be purchased here.
ISG Lab Updates and Reports
Despite the early hour and record breaking low temperatures the event was well attended. You can download my PowerPoint presentation “GL Gem Spectrometer and Advanced Gem Testing” held at the Arizona Hotel here (PDF); the video-clips can be watched at the GL Gem Spectrometer page or in the GLGemSpec support area.
Dr. Bill Hanneman who also attended the meeting has made available for download his Diamond Cut Grading Simplified (PDF) approach; a simple method and workable alternative to other grading systems.
ISG Andesine exhibit: Feldspars that provide Mexican and Tibet R.I.s
In the “ISG Lab Updates and Reports” Robert James reported on several feldspars that showed only partial treatment in one area of the stone. Testing these stones with a refractometer two distinct refractive index readings were obtained on the same table of the same feldspar by just reading over the treated and untreated areas: one typical for Mexican, the other for reported Tibetan. Here is the link with more details about his research: ISG: Andesine the Final Chapter (PDF).
Also visit Tibet Andesine … the true story website.
Planning for Tucson 2012
We are already planning for 2012 with practical workshops and seminars to be held later in the week. Please contact me if you are interested in contributing to an event; any help is appreciated. More information in the CIGem Newsletter Spring 2011.
Synthetic/Imitation “Ruby” Flooding the Market
For several years I have been warning students and consumers about this “very attractive” material.
During the Tucson shows quite a few dealers were selling stones undisclosed at prices ranging from $ 1 – 100/ct. The market is being flooded with this worthless material.
Consumers are not fully aware about possible problems when these stones are set in jewellery.
Whether this material should be called “composite ruby” or “composite glass” depending on the percentage of ruby or glass content is irrelevant. The material does not occur in nature and is man-made; if it has the same properties as its natural counterpart it should be properly named “synthetic ruby”. However, the material lacks the hardness and toughness of natural ruby.
If the original material is some kind of corundum and is consequently filled using lead glass and other substances in order to give it the appearance of ruby it should be called “imitation ruby” – a term I recommend.
This material should be refused by laboratories as it is essentially worthless material and easily recognizable. People selling or appraising this material as “ruby” are running the danger of being sued for misrepresentation. I have encouraged and will support clients who bought this material and were misled. They should request refunds and/or seek remedy through legal channels such as the small claims courts.
During the AGTA show a lady showed me several tourmaline crystals given to her by her father who operates one of the Paraiba mines in Brazil. I tested them on the GL Gem Spectrometer and they did not show any copper content. The crystals displayed a very nice deep bluish-green colour but were lacking the “neon” effect. According to the LMHC definition her tourmalines cannot be called “Paraiba” though the crystals were coming directly from there! From what she was telling me I did not question her credibility as to the source.
A few days later a Brazilian friend contacted me about a purple elbaite tourmaline from Africa in which presence of Mn and Cu was detected using a x-ray fluorescence (XRF) spectrometer. The African seller was interested in getting the “Paraiba” designation for his stones based on the copper content.
And Yes, I bought – not in Tucson but recently on e-Bay – a blue “Paraiba” tourmaline weighing 3.10 ct for $ 86 (valued at $ 5,800 by the seller), it is copper bearing and has a nice “neon effect”. A gem dealer friend looked at the stone and suggested to offer it for sale at $ 2,000 as a starting point. No further comment!
If interested go to e-Bay and search for “Paraiba Torumaline”; there will be over 3,000 offers – buy at your own risk. If you want it tested for copper contact me.
GLGemSpec Version 2.4
All users should have received the update to version 2.4 of the GLGemSpec program.
Version 2.4 saves recent settings and runs under both Windows 32/64 bit systems.
A copy of Bill Hanneman’s recently published new book “Pragmatic Spectroscopy for Gemologists” was sent to all GLGemSpec users; please let me know if you did not receive yours.
LOWER PRICE: The price of the basic GLGemSpec system has been reduced to $ 1,495; we now accept PayPal payments.
Visit the Gemlab Instruments Store.
Interesting Absorption Band Seen in Beryls
After checking a larger number of beryls (yellow, blue and pink colours) we frequently noticed an absorption peak in the 950 – 960 nm NIR range.
Consulting the on-line reference spectral database (Caltech Mineral Spectroscopy Server) we found the following possible explanation: “In the spectra of all these minerals, sharp features in the near-infrared region arise from water molecules in the c-axis channels of the beryl structure.”
B.C. Gem and Mineral Show
Visit the C.I.G. booth
Books and Gem Instruments Sale (up to 50% off only during the show), special C.I.G. display “Vintage Gem Testing Instruments”, demonstrations and more.
C.I.G. Update Classes
GEM 250 – 1 Update Course (for 2010 class): Sat – Wed, May 21 – 25, 10 a.m. – 4:30 p.m, Richmond, B.C., Airport Hotel
GEM 250 – 2 Update Course (for 2011 class): Sat – Wed, Nov. 12 – 16, 10a.m. – 4:30 p.m. Richmond, B.C., Airport Hotel
Advanced Gem Identification for GLGemSpec users (free)
- Spring Session:Wed, May 25, 10 a.m. – 12:30 p.m., Richmond, B.C., Airport Hotel
- Fall Session: Wed, Nov 16, 10 a.m. – 12:30 p.m., Richmond, B.C., Airport Hotel
At the moment Gemlab R&T is not offering gemmological services to the trade or general public. However, Accredited Gemmologists (C.I.G.) in good standing have access to our testing services.
Wolf Kuehn, B.A., M.A., Dipl.oec, F.G.A., F.G.G. – GLR&T Project Manager
© 2011 Gemlab Research & Technology, Vancouver, Canada