GL Newsletter June 2011

Canada Post Labour Disruption

By the time you read this newsletter Canada Post should be back to work. We will process all orders as soon a possible; please be patient as there will be some delays.

Save $ 100 on GL Gem Spectrometer

This is an opportunity to purchase a GL Gem Spectrometer system for a lower price (limited time and quantities); sold to users in over 15 countries our spectrometer is an advanced testing tool for the professional gemmologist. See detailed product information here.

In the last 9 months since introduction we have improved the firmware and software to make the spectrometer more efficient.

As part of our commitment we offer a generous warranty and upgrade policy.

Due to the Canada Post strike we have extended our sales until July 15, 2011

Please order here

Calibration Problems with Chinese made Refractometers

We have tested several  refractometers from China and made some observations which are of importance to beginner gemmologists (and perhaps to the experienced as well). Almost all units we inspected were NOT properly calibrated.

In particular the model sold for under $ 100 like in the packaging to the left had variations of up to .010 for refractive index which could lead to wrong identification when unaware of the deficiency. We opened one of these units and discoverd that all the movable parts in the instrument were glued together and modification was impossible.

The 2 models sold in our on-line store can be adjusted after disassembly. We use a reference stone of RI=1.4703 to calibrate all units before shipping.


In the past we have sold refractometers with a built-in LED which provides a satisfactory mono-chromatic light source; however, users report about drained batteries after putting the refractometer back in the protective pouch and being accidentally switched on again.

We recommend our GL Portable Refractometer (with an external flashlight); you can purchase it here.

A Portable Polariscope and Dark-Field Scope

We are always looking for ways to make gem testing instruments more portable. The GL 5 LED Light Box provides an effective light base for the GL Portable Polariscope and the GLDarkfield 10X Loupe and other instruments such as refractometer, dichroscope and filters.

We have tested several gem testing tools with the GL 5 LED Light Box including the dichroscope and hand-held spectroscope (be aware of transmission typical for this type of LED) and 20x loupe; it operates on 3 AAA batteries.

The image to the left shows the GL Portable Polariscope mounted ontop of the 5 LEDs and unmounted. It is easily replaced by the GL Darkfield 10x Loupe making it into a versatile portable mini microsope with darkfield.

The light output of the 5 LEDs is quite strong. Fracture filled diamonds and types of glass filling are easily identified.

The polariscope has a removable immersion cell allowing undistorted view of inclusion features when used with the proper immersion liquids.

We highly recommend this light unit in combination with the mentioned portable gem testing tools.

Study Stones for Be-treated Sapphire and Filled Rubies

We have started offering a variety of study stones for reference purposes. Many Be-treated sapphires can be identified when detecting features such as seen in the study stones; filled rubies are easier to spot. In the coming weeks we will offer other additional stones in the on-line store. We also have several Colombian emerald (Muzo) specimen for sale.

Click for Be-treated sapphire and lead filled ruby samples.

Understanding Rough Gemstones

We received an interesting book which we highly recommend. If there is enough interest we will carry it in our on-line bookstore.

Whether one is a novice in the field of gemology or a veteran, Understanding Rough Gemstones, by Shyamala Fernandes and Gagan Choudhary, will definitely give one a refreshing and relevant view of gemstone rough.

Perhaps what makes this content of this book so intriguing is the fact that both authors have been closely associated with gemmology for practically their entire lives. They are not only incredibly passionate about the subject but also very well-read. The book manages to teach the reader a whole lot without becoming, at any point, monotonous or heavy.

Whether a student or a veteran gemologist, we are sure that there will be some gems of knowledge in this book for everyone. Loaded with picturesque photographs and characterized by charmingly simple writing, this book is must-readl!

Pages: 211 with many illustrations, images, reference tables, etc. Cost is approximately $ 35 plus shipping from India.

Call Helen D Souza at IIJ Tel 022 67444355 or email


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

© 2011 Gemlab Research & Technology, Vancouver, Canada