The French Gem Connection

Gem-A Accredited Teaching Centre (ATC) the Laboratoire de Gemmologie de Marseille (LGM) recently held its 5th Annual Gemmologist Conference. Katherine Palthey FGA, one of the speakers at the event summarises the day. 

On Sunday 11 December LGM held their Conference at the Mercure Hotel in Marseille France. The Director Agata Cristol FGA DGA organised a successful Conference with guests such as Thierry Pradat FGA of Gems-Plus and guest speakers Alexandre Eichler FGA, Katherine Palthey FGA, Laurent Seneca FGA and Bruno Cupillard FGA.

The topics discussed during the Conference were centered on gem treatments and their impact on retail prices. Alexandre Eichler FGA, Director of Gems River, specialises in sapphires and has spent months in numerous sapphire mines this year confronted with both ‘old burn’ (traditional heating) and ‘new burn’ (heating with diffusion) treatments. He pointed out in detail the differences between the methods and the impact they have on today’s market prices. 

Natural unheated sapphires, LGM blogpost
A rare pair of 6.01 ct natural unheated sapphires from Bo Phloi. Photo credit Alexandre Eichler, Gems River

Katherine Palthey FGA, Gem Expert Consulting, presented Burmese lavender jadeite and the origins of its colour, which is manganese. Burmese lavender jadeite shows an absorption band at 437 nm and a large absorption near 580 nm for manganese. Colour treated jade and imitations have a different spectrum, demonstrating they are not Burmese lavender jadeite. After an intricate explanation on differentiating natural jade from treated jade (shown in the figure below) she announced her research results on over 50 jadeite pieces and shared her inside secrets on how to identify high quality jadeite.

Burmese lavender jadeite options A,B, and C in LGM blogpost
L-R: Burmese natural lavender jade, colour treated jade and an impressive imitation made of Calcite. Photo credit Katherine Palthey FGA, Gem Expert Consulting

Laurent Seneca FGA lives between Colombia and Monaco and dedicates his time to fine quality Colombian emeralds. Laurent explains how the past 20 years have seen an enormous increase in the use of synthetic epoxy resins to enhance emerald’s clarity. He has seen an alarming rise in polymer resins such as Gematrat and Permasafe, being used on Colombian emeralds and he explained the long term implications of these treatments. In the Bogota market alone, he estimates up to 95% of the emeralds today are being treated with hardened epoxy resins.

Colombian emerald, LGM blogpost
1.4 ct natural emerald from Muzo, Colombia. Photo credit Laurent Seneca FGA

Demonstration stations with microscopes between lectures were busy as guests rushed to see the latest in sapphire, jadeite and emerald treatments being introduced to the market this year. There was so much interest, Agata extended the day by an extra hour for our guests.

Guest of Honor, Bruno Cupillard FGA from Aventures Cristallines rounded up the day’s talks. Bruno is a successful mineral and gemstone photographer known for his unique and emotionally triggering views inside gemstones. The audience was taken behind his camera to see his secret photographic techniques, and he generously shared his tips on diffused lighting, background settings and more. He shared a breathtaking video on his photos of scenes and nature’s beauty presented in inclusions such as Paesine – a limestone that has split and shifted to create a scenic landscape…we were all mesmerized. 

Hotel Mercure served us their lovely French cuisine and after digesting our expressos, we jumped in to the Annual Gemmology Tournament. Organised by Thierry Pradat FGA of Gems-Plus, we were each passed 40 different gemstones and with one minute and just the loupe, we had to identify with precision all the material. The ambiance was relaxed and laughter bounced off the walls, although all eyes were on their loupes. Thierry Pradat FGA is one of France’s largest gemstone dealers and his business Gem-Plus is a true reference point for professional jewellers, designers and avid collectors. Thierry generously offered an amazing rhodolite garnet for the winner who was none other than our guest speaker Bruno Cupillard.

Thierry Pradat LGM blogpost
Thierry Pradat introducing the Annual Gemmology Tournament

Agata Cristol FGA DGA, took another minute at the close of the Conference, while waving the Gem Guide, to remind all of us to be cautious when classifying treatments on certificates and disclosing them to customers. The overall aim of the discussion was seeking international agreements on classifying treatments within these materials and to improve our commitment to ethical mining issues such as dynamiting the beautiful mountains in Colombia. A wonderful experience and I look forward to Conferences such as these in the future. ■  

Interested in finding out more about diamonds? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image 2016 Conference Speakers and Cecile Agu FGA. L-R: Alexandre Eichler FGA, Cecile Agu FGA, Katherine Palthey FGA, Bruno Cupillard FGA, Thierry Pradat FGA and Agata Cristol FGA DGA.


Gem Central Delving into Organics with Maggie Campbell Pedersen FGA ABIPP

Gem Central Delving into Organics with Maggie Campbell Pedersen FGA ABIPP

Gem-A president and organics expert Maggie Campbell Pedersen presented the April Gem Central at Gem-A headquarters. Angharad Kolator Baldwin reports on this fascinating evening...

Read more


Nuummite – the Origin of Colour

Nuummite – the Origin of Colour

This article by Guy Lalous ACAM EG summarises a technical article from The Journal of Gemmology discussing the origin of colour and conditions of formation in violet-to-blue Nuummite from Simiuttat, Greenland...

Read more


Gem Central Exploring Ruby Treatments with Julia Griffith FGA DGA EG

Gem Central Exploring Ruby Treatments with Julia Griffith FGA DGA EG

Gem-A gemmology and diamond tutor Julia Griffith FGA DGA EG led a gem central titled Exploring the Differences between Glass In-filled, Flux Healed and Lead Glass-filled Ruby, in an informative and engaging gem central evening. Julia summarises the evening here for those that missed out...

Read more


Digital Gems and Instagram Stars: How the Internet Is Boosting Gemmology

Digital Gems and Instagram Stars: How the Internet Is Boosting Gemmology

Holly Mowle, a current Gem-A Diploma Student, discusses how the internet has become a treasure trove of lapidary and jewellery items, old and new. In this article she explores the use of web space platforms by lapidaries today to develop a virtual artistic presence.

Read more