CIGem News Spring 2015

ISSN 0846-3611 GEMMOLOGY CANADA – Wolf Kuehn, F.G.G., F.G.A., Editor

From the Editor:

Alphof Faschina The New Year 2015 started right away with the 17th FEEG Symposium in Brussels (Belgium); it was held  in the “Royal Windsor Hotel” on the 17th of January .I had the pleasure to talk to many European colleagues some of whom I met again in Tucson, Arizona  two weeks later.

 

After the conference I spent a week skiing near St. Anton am Arlberg  in Austria where the Haute-Volée (High Society) spends their winter holidays; less than 70 km away in Faschina-Fontanella I had the lifts to myself and spend less than US$ 80 per night (breakfast and dinner included) at the Hotel Alphof  which I can highly recommend.

The  AGTA Gemfair in Tucson, February 3 – 8 was better attended than in past years; however, the high value of the US$ limited the buying power of foreign visitors. We had many old friends from around the world drop by the C.I.G. booth and have a look at the new GL Gem Spectrometer NIR PL405 unit.

BC Gem Show, Abbotsford BC, April 10, 11 & 12, 2015

BC Gem Show 2015 Many Club Displays, Demonstrations, Grab Bags, Children’s Creative Workshop, Gold Panning & Door Prizes.

  • Friday: 10:00am – 8:00pm
  • Saturday: 10:00am – 6:00pm
  • Sunday: 10:00am – 5:00pm

 

The  GL Gem Raman PL532 will be demonstrated; like last year we will test gems and minerals during the show (2 items per visitor) with our advanced spectrometer equipment (only oral opinions will be given). We also have books, basic gem testing equipment, study stones and some used items, etc. for sale.

A new Vancouver Gem & Mineral Show is scheduled for later in the summer (August 14 – 16) which we will also attend.

Photoatlas of Gemstone Spectra for Gemology Students

Photo Atlas Spectra This new book with gemstone spectra has been published by Richard D. Armstrong, RGA, GG, GP.Please read a review by the The Practical Gemologist blog; we highly recommend this valuable reference book.

Mark your calendar for these upcoming gem conference

Mediterranean Gemmological and Jewellery Conference

Athens Athens, Greece, June 27th and 28th, 2015Take in a conference of incomparable atmosphere and learn from some of the world’s top independent lab gemmologists, appraisers and gem experts who are highly trained and equipped with the best tools for testing, grading and appraising.

We are getting ready for this exciting meeting; the GemConference website with registration page is now up. More details to follow soon.

News from Gemlab Research & Technology

GL Gem Spectrometer™ – 2015 edition

Detection of polymer treated jadeite
Ruby

Comparison of various rubies

Pink Diamond

Pink Diamond, HPHT treated, irradiated (405 nm laser excitation, room temperature)

Many GL Gem Spectrometer users have been asking whether their instrument could be used with UV LEDs or inexpensive laser pens. Using UV excitation sources not only requires solarization-resistant fibers and  protective eye glasses (also important for lasers) but could cause diffraction problems in the spectrometer. Former spectrometer users (up to model 2014) can purchase the  GL Analyzer PL405 Kit  which includes a filter to eliminate some of these effects caused by the blue laser (405nm).

We have now installed a diffraction order sorting filter for elimination of second order effects; this will work with SW and LW UV light sources and lasers. For the 2015 models we offer a GL Analyzer PL 405/GL Xenon Flashlight combo for the same prize (Long Wave Pass Filter not included as it is not necessary in the new model).

GL Analyzer PL405 Kit again in stock

PL 405 Kit Now available  – for GL Gem Spectrometer (up to model 2014) owners who do not want to assemble a similar kit on their own – a complete package which includes proper laser safety goggles.The GL Analyzer PL405 kit converts the GL Gem Spectrometer into a “poor man’s version” of a PL spectrometer as found in the GL Gem Raman PL532 system .

The GL Gem Spectrometer in PL mode can be used to identify gems and minerals by their chromophores; there is also great potential for diamond characterization. It will detect the GR1 center for irradiated diamonds, the Si center often seen in CVD grown diamonds (in some cases without LN cooling) and polymer treatment in jadeite.

Raman Spectrometer Setup and Tutorial

We are providing this  important service package for purchasers of the GL Gem Raman PL532 system who may need assistance in setting up and operating the Raman spectrometer.

The cost of this service is based on average travelling expenses including airfare, accommodation and a reasonable amount of remuneration for the tutor/instructor.

The total cost will include a six (6) hour tutorial which can be attended by up to 5 persons; additional time can be added at $ 75 hourly rate.

Please contact us for an estimate or if you want to incorporate this workshop into your conference program, meeting, etc. This service is also available to previous buyers of the GL Gem Raman and GL Gem Spectrometer.

For Europe, South America and Far Eastern countries the total price will be around US$ 2,000; for North America US$ 1,000 (assuming fuel prices remain low).

Gem Forum Friday, Nov. 13/14, 2015
The fall meeting of members of the “Gem Connoisseur Club”, students and friends of the Canadian Institute of Gemmology; all Accredited Gemmologists (C.I.G.) and former C.I.G. students are welcome.

There will be several workshops available. Program T.B.A. soon.


CIGem News Winter 2014

ISSN 0846-3611 GEMMOLOGY CANADA – Wolf Kuehn, F.G.G., F.G.A., Editor

From the Editor:

Mt. Fitz Roy, Patagonia

Mt. Fitz Roy, Patagonia

After a busy fall season the year 2014 is coming to a close. With several talks and workshops in Sao Paulo, Porto Alegre and Rio de Janeiro my Brazil trip ended with an exciting excursion to the Ametista de Sul mining are. I also had the opportunity to visit one of the destinations  on my wish list: Patagonia, Argentine with 2 days of trekking in the Monte Fitz Roy (3,405 m) range .

I am writing this while still in Thailand after attending GIT2014 Conference in Chiang Mai and “recovering” from the post-conference journey to sapphire mines and a trip to the Golden Triangle bordering Burma and Laos.

On January 17, 2015 I will be at the FEEG Symposium in Brussels with a presentation; next is Tucson for the annual AGTA GemFair from February 3 – 8. Early in the summer planned is the first Mediterranean Gem Conference in Athens, June 17 and 18.

I wish you all a Healthy and Happy New Year 2015. 

Brazil Tour 2015

During my annual visit to South America I  could meet many old friends;  all the Raman units installed In Brazil last year have been performing well. The itinerary included Sao Paulo, October 29 at IBGM, Porto Alegre, November 4 – 5 at Instituto de Geociências – UFRGS followed by a field trip and Rio de Janeiro, November 10 – 12 at CETEM.

Amethyst Geode

Amethyst Geode

Amethyst Shop, Ametista Brazil

Amethyst Shop

Ametista Church

Church in Ametista do SUl

Wein Keller

Wine cellar in Ametista mine

IBGM SaoPaulo

Spectrometer presentation at IBGM, Sao Paulo

Cetem Workshop

Workshop at CETEM, Rio de Janeiro

Ametista do Sul, Brazil 

After completion of the 3-day seminar at the Departamento de Mineralogia e Petrologia do Instituto de Geociências da UFRGS in Porto Alegre  a small group went on a 3-day field trip to the amethyst mines and other gem and mineral localities in Rio Grande do Sul, Brazil.
 
I want to thank Prof. Dr. Pedro Juchem  for the invitation to participate in this amazing tour. We also visited the Ametista Parque; for your information please download field trip guide (PDF).
 

GIT 2014 in Chiang Mai, Thailand

The conference was well organized and a great success with many attendees visiting the GL R&T booth where the new GL Gem Spectrometer NIR PL405 was on display; download our poster “Raman and Photoluminescence Spectroscopy in Mineral Identification (PDF, 856 KB)”

You can also download the Proceedings with all abstracts from here (PDF). Following are a few images from the Facebook page of The Gem and Jewelry Institute of Thailand.

Elephant Conservation

Thai Elephant Conservation Center (TECC)

Sapphire Mine

Phrae Sapphire Mines – Sukhothai

Northern Thailand Dance

Dinner Party at Phrae Governor’s House

As always both the pre- and after-conference excursions were lots of fun and interesting. We are already looking forward to participating in GIT 2016.

FEEG Symposium Brussels, Belgium, January 17

FEEG

FEEG Conference

The Societe Belge de Gemmologie of Brussels (SBG) has the pleasure to invite you to the 17th FEEG Symposium in Brussels (Belgium) that will be held on the 17th of January 2015 in the “Royal Windsor Hotel”. For more information go to the FEEG Symposium website.

My presentation will demonstrate the the usefulness of Raman and introduce low cost photoluminescence (PL) spectrometry for gemmologists using blue (405 nm) laser excitation. 

Gemlab Research & Technology has sponsored the event and will have a demonstration table for the GL Gem Raman PL532 TEC system.

Mediterranean Gemmological and Jewellery Conference June 27/28

The National Association of Jewelry Appraisers (NAJA) has posted a first announcement of this important conference on their Facebook page. You can download the tentative program from here (PDF). For further information and registration go to the GemConference website.

News from Gemlab Research & Technology

GL Gem Spectrometer NIR PL405 available now.

GL Gem Spectrometer NIR PL405

GL Gem Spectrometer NIR PL405

Introduced during the 4th International Gem and Jewelry Conference (GIT2014)  the GL Gem Spectrometer NIR PL405 is a dual purpose spectrometer for photoluminescence (PL) spectroscopy.

It can be used for VIS-NIR spectroscopy (550 – 1,000 nm) as well as the GL Halogen Gem Holder is included.

The new spectrometer has a higher resolution than our regular unit, a Long Wave Pass Filter (LWPF) and is optimized for the NIR range.

GL Analyzer PL405 Kit

PL 405 Kit

GL Analyzer Kit PL405

Now available  – for those who do not want to assemble a similar kit on their own – a complete package which includes proper laser safety goggles. 

The GL Analyzer PL405 kit converts the GL Gem Spectrometer into a “poor man’s version” of a PL spectrometer as found in the GL Gem Raman PL532 system .

The results for obtaining luminescence spectra from ruby, sapphire, emerald, spinel, alexandrite, etc. are very good. It has great potential for diamond characterization; work with a liquid nitrogen (LN) attachment has been started.

Upgrade for Spectrometer

Upgrade Kit

GL Gem Spectrometer Upgrade Kit

All 2014 and newer models of the GL Gem Halogen Light holder mounted onto the spectrometer come with a thicker base plate which allows easier positioning of the sample on the Teflon disk (it cannot not slip off ). This upgrade kit may be of interest to purchasers of the GL Gem Spectrometer prior to 2014.

The upgrade kit with all necessary parts is available for $ 40 (includes shipping anywhere in the world).

Calibration

After air travel or strong temperature changes I noticed that the  GL Gem Spectrometer may become slightly out of calibration. Though not a critical problem users should check the accuracy of their instrument with the supplied synthetic ruby. A service program can be downloaded from the GLGemSpec user section to re-calibrate the instrument quickly and safely.

GL Gem Raman PL532 Laser Options

We decided to offer a 200 mW and 300 mW laser option for the GL Gem Raman system. We found that some users did not take the warning seriously to use care when dealing with amber and pearls. We recommend the 200 mW option for appraisal work and gem labs and the 300 mW laser for testing minerals and samples with rough surfaces.

GLBPF (filter) Upgrade

GLBPF

GL Band Pass Filter for Raman

As a reminder the GL Gem Raman Band Pass Filter (GLBPF) for suppression of fluorescence in Raman mode is now available as a kit.

It consists of a holder with a dielectric filter which is inserted into the GL Gem Raman case when needed.

This simple solution allows the upgrade of all GL Gem Raman units previously sold for a reasonable price (dielectric filters are not inexpensive!). 

GL Gem Raman users should note that the TEC option is beneficial only for exposure times over 1,000 ms; for regular work with gemstones it does not need to be turned on.

Raman Spectrometer Setup and Tutorial

We are providing this  important service package for purchasers of the GL Gem Raman PL532 system who may need assistance in setting up and operating the Raman spectrometer.

The cost of this service is based on average travelling expenses including airfare, accommodation and a reasonable amount of remuneration for the tutor/instructor.

The total cost will include a six (6) hour presentation/tutorial which can be attended by up to 5 persons; additional time can be added at $ 125 hourly rate. This package could be of interest to conference organizers as well.

Please contact us for an estimate. This service is also available to previous buyers of the GL Gem Raman and GL Gem Spectrometer.

For Europe, South America and Far Eastern countries the total price will be around US$ 2,000; for North America US$ 1,000 (assuming fuel prices remain low).

AGTA GemFair Tucson 2015

AGTA

AGTA Tucson 2015

 

It is not too late to plan for the Tucson gem shows; please drop by at the C.I.G. booth #31 at the Galleria Level of the AGTA Gemfair in Tucson, February 3 – 8, 2015.

I will be present at the booth every day from 9:00 a.m. until 5:30 p.m.

To register follow this link.

CIGem News Fall 2014

ISSN 0846-3611 GEMMOLOGY CANADA – Wolf Kuehn, F.G.G., F.G.A., Editor

From the Editor:

As last year I spent 10 days mountaineering in the Dolomites mountains in South Tyrol, Italy. The weather was not the best with daily thunderstorms as Europe had probably one of the worst summers. This time I was interested in the area around the Falzarego Pass (Passo di Falzarego) which was the object of heavy combat in World War I. I hiked a trail secured with steel ropes and bridges up to the summit of the  Lagazuoi (2762 m) and could only imagine the terrible sacrifices the parties involved made. The tunnel that the Italians built under the Austrian lines is open to the public.

Dolomites

Dolomites, South Tyrol

Trail

Trail to Lagazuoi (2762 m)

Nuvolau

Refugio Nuvolau (2575 m)

Exhibitor at the 2014 GSA Meeting in Vancouver, B.C. (19–22 October 2014)

GSA 2014 I would like to invite you to the GSA2014 meeting (October 19 – 22) in Vancouver, B.C. which will attract over 7,000 geoscientists from around the world.

Please download and print out your VIP pass which will allow a one time entrance into the exhibit hall.

The Canadian Institute of Gemmology (C.I.G.) and Gemlab Research & Technology (GLR&T) will be exhibiting at booth #552 (next to Networking Lounge) at the Vancouver Convention Centre, 1055 Canada Place during the Geological Society of America annual meeting (GSA 2014).

“Discover new science in the 247 topical sessions, trips, courses, and events. GSA is where geoscience professionals come to get engaged, get educated, get inspired, and enjoy each moment.”

There are many gemmology related events on Monday, October 20.

GL Analyzer PL405 Kit

On the facebook page for the GL Gem Spectrometer we introduced – for those who do not want to assemble a similar kit on their own – a complete package which includes proper laser safety goggles.

The GL Analyzer PL405 kit converts the GL Gem Spectrometer into a “poor man’s version” of a PL spectrometer as found in the GL Gem Raman PL532 . The results for obtaining luminescence spectra from ruby, sapphire, emerald, spinel, alexandrite, etc. are very good.

The GL Gem Spectrometer in PL mode can be used to identify gems and minerals by their chromophores; there is also great potential for diamond characterization. It will detect polymer treatment in jadeite (see below).

Detection of polymer treated jadeite with the GL Gem Spectrometer

The GL Gem Spectrometer™ is very efficient in detecting whether green jadeite has been treated or not.

Jadeite Polymer Treated Jadeite Untreated

With a blue laser (405 nm) excitation source (GL Analyzer PL405 Kit recommended) a strong luminescence band appears in the green wavelength range of polymer treated jadeite which is absent in untreated green jadeite.

You can use your own blue laser pointer (use safety goggles!) to test your green jadeite samples; detailed instructions are in the user section.

Download jadeite info sheet (PDF, 540KB).

For your own protection always use laser safety goggles when operating any type of laser equipment.

Workshops in Brazil

I have planned several workshops and presentations both about advanced spectroscopy and visits to gem mining areas in Colombia, Australia and Myanmar/Thailand/Cambodia in Sao Paulo, Porto Alegre and Rio de Janeiro, Brazil; if you want to participate please contact me or the institutions.

Sao Paulo, October 29 at IBGM

Porto Alegre, November 4 – 5 at Instituto de Geociências – UFRGS followed by a field trip to mines near Soledade.

Rio de Janeiro, November 10 – 12 at CETEM

Gemlab R&T Official Sponsor of GIT 2014, Chiang Mai, Thailand

We have submitted an extended abstract for a poster session, download  “Raman and Photoluminescence Spectroscopy in Gem Identification” (PDF), 358 kB

GIT2014 Official Sponsor 4th International Gem and Jewelry ConferenceChiang Mai, Thailand Dec. 8 – 9, 2014

In our booth will be releasing and demonstrating the new GL Gem Spectrometer NIR PL405.

GL Gem Spectrometer NIR PL405 RELEASE SOON

Planned for release during the 4th International Gem and Jewelry Conference (GIT2014)  in Chiang Mai, Thailand Dec. 8 – 9, 2014 the GL Gem Spectrometer NIR PL405 is a dual purpose spectrometer for photoluminescence (PL) spectroscopy; it can be used for VIS-NIR spectroscopy (550 – 1,000 nm) as well (the GL Halogen Gem Holder is included).

The spectrometer has a higher resolution than our regular unit, a Long Wave Pass Filter (LWPF) and is optimized for the NIR range.

GL Gem Spectrometer NIR PL405

GL Gem Spectrometer NIR PL405

Red Spinel, Burma

It allows identification of many gemstones such as ruby, sapphire, emerald, spinel, alexandrite, etc. based on their PL response and also has great potential for diamond characterization. It can be used in addition to the GL Gem Spectrometer or on its own as a dedicated PL and transmission spectrometer as many gem materials have important features in the VIS-NIR  range.

For instance it will identify untreated or treated jadeite (it will not show the PL band for polymer treated jade though due to the built-in LWP filter). Diamond irradiation, copper content in “Paraiba” tourmaline will be visible in the spectrum. First studies indicate that heat treatments such as in red spinel can be determined.

In PL mode it is almost as sensitive as the GL Gem Raman PL532 and can serve as a low-cost PL spectrometer.

We will have a display booth at  GIT2014; more info http://www.git2014.com/index.php

GL Gem Raman PL 532 Demo Unit FOR SALE

We still have a GL Gem Raman PL 532 demo unit (without TEC) for sale. This instrument with its extended range has been upgraded and equipped with the GLBPF (see band-pass filter upgrade) and is ideal for a small laboratory or as a teaching instrument in a college or university.

AGTA GemFair Tucson 2015

AGTA It is time to get ready for the Tucson gem shows; please drop by at the C.I.G. booth #31 at the Galleria Level of the AGTA Gemfair in Tucson, February 3 – 8, 2015.

I will be present at the booth every day from 9:00 a.m. until 5:30 p.m.

To register follow this link.

GL Newsletter July 2014

Bonne Terre Mine

Bonne Terre Mine

From the editor

One of the highlights of the GeoRaman conference was the field trip “Historic Lead Mining in Missouri” to the Bonne Terre Mine and Museum; one would expect the typical abandoned lead mine instead we visited the world’s largest fresh water dive resort!

We took a guided boat tour on the “Billion Gallon Lake” (the world’s largest subterranean lake) with its crystal clear water, and spectacular views of Underground Flower Gardens, Calcite Falls, and ancient Abandoned Mining Tools and Rail Systems.

I want to thank the organizers and helpers of GeoRaman 2014 for a memorable week in St. Louis, MO.

Please note that I will be away from the office from August 24 until September 17 while travelling in Europe.

For November several conferences/workshops are planned for Brazil including a one week seminar/field trip to the amethyst mines in Rio Grande do Sul (Porto Alegre). Please contact me regarding these events.

11th International GeoRaman Conference

GL R&T was a sponsor of this well attended conference and had a display booth demonstrating the GL Gem Raman PL532 TEC and the GL Gem Spectrometers. Several researchers were impressed by their performance and versatility and are considering to purchase the Raman unit as a teaching instrument in geoscience classes.

Our poster “Raman and Photoluminescence Spectroscopy in Mineral Identification (PDF, 856 KB)” for GeoRaman 2014 was well received; the full program (PDF) with links to abstracts can be accessed here.

Of particular interest were the following contributions:

Study of the Composition of Amphiboles in the Tremolite — Ferro-Actinolite Series by Micro-Raman and SEM-EDXS (PDF) by researchers of the University of Parma, Italy, Physics and Earth Sciences Department. Several co-authors dropped by the GL R&T booth and explained their findings with a sample of nephrite using the extended range of GL Gem Raman PL 532.

Machine Learning Tools for Mineral Recognition and Classification from Raman Spectroscopy (PDF) by researchers from the School of Computer Science, University of Massachusetts, USA

Identification of CVD Synthetic Gem Diamond Using Raman Spectroscopy (PDF) by W. Wang, GIA, New York, USA

A special session in the Washington University’s Imaging lab was offered to a small group of participants. Go to GLGemRaman Facebook Photo gallery for more information.

The next GeoRaman XII will be held in Novosibirsk, Russia in 2016.

GL R&T Bronze Sponsor at the 4th International Gem and Jewelery Conference (GIT 2014 )

GIT2014 We are getting ready for the next conference.

GLR&T is Official Sponsor with an exhibition booth at the 4th International Gem and Jewelry Conference in Chiang Mai, Thailand Dec. 8 – 9, 2014

More info http://www.git2014.com/index.php

GL Gem Raman PL 532 Demo Unit FOR SALE

We have a GL Gem Raman PL 532 demo unit (without TEC) for sale. This instrument with its extended range has been upgraded and equipped with the GLBPF (see band-pass filter upgrade) and is ideal for a small laboratory or as a teaching instrument in a college or university.

American Cut the First 100 years

American Cut We received from the GIA Bookstore a complementary copy of this excellent treatise by Al Gilbertson, G.G.

“Have you ever looked at a beautifully designed and finely crafted piece of antique jewelry and wondered why the diamonds look so different than the ones in modern jewelry?”

 

This book chronicles the evolution of what we refer to as the Ideal Cut from its earliest beginnings. It is still available from Amazon.

GEM 250 Workshops scheduled for September

This advanced workshop will be offered in Nanaimo, BC from Saturday – Tuesday, September 27 – 30.

Students in the Fine Jewellery Expert (F.J.E.) Program can complete their practical course-work for GEM 150 Gem Identification I; please contact us at 604-530-8569 for more information.

The advanced course GEM 250 will cover the practice and use of the GL Gem Spectrometer and the GL Gem Raman PL 532.

For present and future users we recommend the evening workshop GEM 270.

_________

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

© 2014 Gemlab Research & Technology, Vancouver, Canada

GL Newsletter May 2014

logo21-150x150 From the editor

As we are approaching the busy months of this year just a few reminders:

There are few places left during our Spring 2014 PDP (Professional Development Program) at the Sandman Signature Hotel – Vancouver Airport, May 31 – June 3. More info here.

The program for the 11th International GeoRaman Conference (June 15 – 19) in St. Louis, MO USA has been published; download program (PDF file which contain links to abstracts).

Please read our abstract (PDF, 356 KB).

GL Gem Spectrometer and GL Gem Raman Workshops

For present and interested future users of our advanced gem testing instruments we offer a free 3-hour review and hands-on session during the Spring 2014 Workshops on Tuesday, June 3 from 2:00 – 5:00 p.m.; the workshop is limited to 5 participants. Please contact us at gemlab@cigem.ca to reserve your space.

We also have an advanced 3 1/2 hour workshop scheduled for Tuesday, June 3, 2014 from 6:00 – 9:30 p.m.; please register on-line by May 20.

GL Gem Raman PL 532 Upgrade

After successful testing of a protoype we have implemented the GL Gem Raman Band Pass Filter (GLBPF) for suppression of fluorescence in Raman mode. It consists of a holder with a dielectric filter which is inserted into the GL Gem Raman case when needed. This simple solution allows the upgrade of all GL Gem Raman units previously sold for a reasonable price (dielectric filters are not inexpensive!); all users will be contacted when the filter assemblies become available (in early June 2014).

The official introduction of the the upgraded GL Gem Raman PL532 TEC (which will be slightly lighter weighing less than 8 kgs) will take place at the GeoRaman Conference (June 15 – 19) in St. Louis, MO USA; as an official sponsor of this event we have a display booth and will be demonstrating the new GL Gem Raman PL532 TEC in the 2014 GeoRaman Exhibition Hall.

After band pass filter for fluorescence suppression

Band pass filters are used in more expensive commercial Raman systems in a number of applications. The introduction of a suitable band pass filter for suppression of fluorescence will greatly improve the detection of Raman signals when previously overwhelmed by fluorescence. We received surprisingly good results with spinels, rubies and sapphires, emeralds and other gemstones affected by fluorescence. In many cases valuable Raman information could be obtained to positively identify the sample in the RRUFF database. However, very strongly fluorescent materials such as synthetic flame fusion ruby could not be identified; for these materials a UV laser in a gated system will be necessary.

The filter assembly can also be used with other filters. As we are able to produce the filter assembly in larger quantities the price of the complete GL Gem Raman PL 532 TEC system has not changed and will be under US$ 8,500 (Can$ 9,300, EUR 6.200). More info about the GL Gem Raman PL532 here.

New Advisor to the GLR&T Team

We welcome J M Dereppe, Ph.D. (Professor Emeritus, Physical Chemistry Department), University of Louvain, Belgium to the Gemlab R&T Development and Support Team. Jean-Marie is running his own research lab and is an experienced spectroscopist who purchased the GL Gem Raman PL532 TEC last year; he is also our European contact person.

Jean-Marie’s work was was crucial in finding a solution to overcoming the fluorescence problems common in Raman spectroscopy. After testing a number of filters he presented me with the idea of a bandpass filter which we now include in all new GL Gem Raman units as the “GL Gem Raman Band Pass Filter (GLBPF) for suppression of fluorescence in Raman mode”.

Articles about Testing HPHT Reated and CVD Grown Diamonds

We were able to test a number of diamond samples and the work is still ongoing (and probablay will for a while). Until now there is no 100% answer as to the type or combination of treatments used on synthetic diamonds (either HPHT or CVD grown); as these materials will become more common in the near future scientist struggle to come up with solutions. As a start an excellent scientific book is by “Inga A. Dobrinets, Victor G. Vins, Alexander M. Zaitsev (2013) HPHT-treated Diamonds”; sample pages can be downloaded from here.

Personally I would be cautious with all devices claiming 100% reliability and repeatability based on a large reference base: only one sample which has not been properly identified will make the whole database useless.

I believe there will be several approaches in the future with analysis of photolouminescence features perhaps the most promising. In this context the PL feature of the GL Gem Raman PL532 will be very useful in future research; the state of the art will be presented during our poster session at the GeoRaman 2014 conference. Below one example of our findings:

Raman PL spectrum (room temp.) indicating HPHT treatment in synth. diamond

Raman PL spectrum (room temp.) indicating HPHT treatment in synth. diamond

The graph above left illustrates a synthetic HPHT treated diamond (non CVD) with a nitrogen-vacancy defect at 637 nm; it also shows the surpression of the 558, 566 and 576nm bands which usually indicate an untreated diamond if the 637 nm peak is missing as well.

Strong silicon-vacancy peak at about 737nm may indicate CVD (chemical vapour deposition) grown synthetic diamond; there are natural diamonds with similar features but they can be recognized by their inclusions. However, the detection of the SiV optical center at 736.6/736.9 nm SHOULD NOT be considered proof of CVD synthesis (see recent article in Gems & Gemology, Spring 2014); more research is necessary.

The analysis of Gr1 and SiV centres in CVD-grown yellow diamonds and the comparison with existing published data indicate that other impurities like Xe, Ni or Cr may produce other colours as well; see “Contributions to Gemology #14 (2014) New Generation of Synthetic Diamonds Reaches the Market, 41 – 55” published by GRS Gemresearch Swisslab.

Exotic Gems, Volume 3 by Renee Newman

Exotic Gems Vol 3 How to Identify, Evaluate, Select and Care For Matrix Opal, Fire Agate , Blue Chalcedony, Rubellite, Indicolite, Paraiba and Other Tourmalines.

This book and other volumes can be purchased at our Gemlab Books on-line store.

I would like to thank Renee for the authographed copy she presented me during the last AGTA Gem Show in Tucson, Arizona; as always a solid work with lots of beautiful images.