GL Newsletter October 2013

From the Editor

AGTA 2014

After travelling in Brazil for three weeks and giving presentations to various university groups including the Federal Police of Brazil during the “II Seminario Iberoamericano de Geologia Forense”(Brasilia, Oct. 2 -4) we are already  preparing for the next AGTA Gemfair Tucson, Jan. 4 – 9, 2014.

The GL Gem Raman PL532 TEC is now being used for scientific research at the University of St Andrews, Scotland (see below) and at The Mineral Technology Center (CETEM) – a research institute of the Ministry of Science, Technology and Innovation (MCTI) in Rio de Janeiro, Brazil.


Understanding Fluorescence 2013, August 31

I attended the one-day Professional Development Course at the Department of Earth and Environmental Sciences, University of St Andrews, Scotland; the workshop was part of a series of events associated with the UK Luminescence and ESR meeting and immediately followed it.

The course was targeted at gemmologists, valuers and jewellery professionals and all individuals interested in gems and minerals. It provided a unique opportunity to expand understanding and use of fluorescence in gemmology and other mineral sciences.

GL Gem Spectrometer reviewed in French Journal

An article about the GL Gem Spectrometer appeared in the French Revue de gemmologie AFG N 183 (2013) (PDF 1.7 MB, with permission by the author)

Developments for GL Gem Spectrometer and GL Gem Raman PL532

We are working on several projects exploring the PL (photoluminescence) features of the GL Gem Raman PL532 for detection of HPHT treatments in diamonds and colour enhancements of gemstones.

I highly recommend a recent publication HPHT-Treated Diamonds – by Springer; you can download the complete Chapter 2 on Diamonds Used for HPHT Treatment.

It provides an excellent overview of the types of diamonds including their atomic models and describes testing methods for coloured diamonds.

Of concern is the statement on page 16 that “HPHT-treated cape-yellow diamonds are also something to encounter within the gem diamond market” as confirmed during a workshop at the September Hong Kong Jewellery Show. Until now we assumed that the cape lines (which are easily detected in the GL Gem Spectrometer) indicated “untreated”.

For a limited time we offer again the GL Gem Raman PL532/Gem Spectrometer Combo (until October 31). We also have one GL Gem Raman PL532 TEC unit for sale in Brazil; please contact me for details.

Identification of Jadeite Treatments with the GL Gem Spectrometer

The light holder of the GL Gem Spectrometer can easily be removed and uses with external light sources; as the halogen and Xenon light have very similar emission spectrum normalized reference spectra can be used for comparison.

First turn light on and take a "reference" (lamp) spectrum

First turn light on and take a “reference” (lamp) spectrum without any sample


Remove the light holder and put some “blu-tack” to level the sample with the entrance port

Place the sample area over the entrance port

Place the sample area over the entrance port


Shine the GL Xenon Flashlight from above onto the sample and observe the spectral graph

If you see the 690 nm peak the jadeite is naturally coloured; if the 690nm peak is missing the jadeite is either dyed or treated. The Chelsea filter reaction may indicate presence of dye.

Identification of dyed jadeite (PDF) from The Journal of Gemmology, 2009, 31(5-8)

Jadeite Untreated Jadeite Treated

The GL Gem Raman PL532 is needed to confirm polymer impregnated jadeite.

Advanced Gem Identification

cig100This 4-day workshop is offered as part of the A.G. Professional Development Program (AG-PDP). Also recommended as an upgrade course for practising gemmologists.

Students will learn state-of-the-art techniques (including immersion-scope, gemstone magnetism, IR-VIS-NIR and Raman spectroscopy), etc. designed to identify confidently any gemstone encountered in the market place.

Between 100 and 120 challenging gems including the most recent synthetics and treatments are available for testing.

  • Fee: $ 995 includes comprehensive study guide, Gemstone Inclusion Library, use of lab equipment and study stones.
  • Date: Sat – Tue, Nov 16 – 19, 10 a.m. – 4:30 p.m., Vancoucer (YVR Airport Hotel), Richmond, B.C.
  • Please register by October 17, 2013

Here a brief list of man-made gems in our study collection: Chatham, Kashan, Ramaura, Knischka, Lechleitner, Regency, Biron, Lenix, Gilson, Tairus rubies, sapphires, emeralds, alexandrite, opal, moissanite, CVD, synthetic diamonds and many others. Gem enhancement techniques such as heat-alteration, surface colour diffusion, irradiation, HPHT and glass filling are studied.

Day 1: Review of gem testing instruments; introduction to advanced identification techniques using the GLGemSpec and GL Gem Raman PL532 spectrometer.

Day 2 and 3: Routine testing with microscope and selected gemmological tools to identify difficult gem materials loose and set in jewellery.

Day 4: Identification of challenging gem materials and their treatments.

GL Gem Raman Workshop

Gemlab LogoThis course is recommended for future users of the GL Gem Raman PL532 system.

  • Using PowerPoint presentations the development and use of Raman spectrometers is introduced.
  • Procedure of proper calibration with Laser Glasses (190-548nm); learning step-by-step testing method with GLGemRaman software and searchable database.
  • Practical testing of a number of interesting gem materials by the participants under supervision of the workshop facilitator.

Fee: $ 295 (limited to 4 participants. To register on-line go here.

Date: Fri, Nov 15 from 6:00 – 10:00 p.m. (4 hours), Vancoucer (YVR Airport Hotel), Richmond, B.C. Please register by October 17, 2013

Participants who purchase a GL Gem Raman PL532 within one month after the workshop will receive a $ 295 discount.

We reserve the right to cancel courses if there is insufficient enrolment; upon return of all course materials students will receive a full refund for the tuition paid but no other compensation can be offered. Please wait with travel arrangements until final confirmation.

View/Download and read carefully our refund policy (PDF).

11th International GeoRaman Conference

“The 11th International GeoRaman conference in St. Louis, June 15-19, 2014 will focus on two major aspects of laser Raman spectroscopy: (1) The most advanced technologies and instrumentation, from laboratories to a wide variety of field applications, e.g., industrial and security monitoring, geo-fields, deep ocean, and on other planets; (2) The newest applications in studying inorganic, organic, and bio-genetic materials in Earth Sciences, Planetary Sciences, Environmental Science, Forensic Science, Archaeology and Archaeometry, Gemology, and Astrobiology.”

During the Xth GeoRaman in Nancy France in June 2012 several gemmology related issues were covered and will be further addressed in St. Louis.


Wolf Kuehn, B.A., M.A., Dipl.oec, F.G.A., F.G.G. – GLR&T Project Manager

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