Gemlab : Gemlab Gemological Laboratory Equipment

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Gemlab is a very well equipped gemmological laboratory working on the necessary level to be able to properly identify gemstones, imitations, synthetics and all treatments possible; in our lab we routinely work with the following instruments:

Standard gemmological equippment

Refractometer, polariscope, dichroscope, lopupe, darkfield loupe and fibreoptic light by GIA Gem Instruments
Diffraction grating spectroscope
LW (365 nm) and SW (254 nm) UV lamp UVP Mineralight UVGL 25
Gold tester TRI Electronics GT-4000
Electronic breakdown voltage tester Moisketeer 2000SD
Precision balance Mettler Toledo CB203 with accessory for hydrostatic weighing.
Precision balance Kern EW600-C3NM
Portable precision balance Tanita Model 1210

Research Grade Binocular Microscope

The top microscope in our lab is a Leica M165C binocular microscope adapted for gemological purposes. The microscope has a continuous zoom from 7.3 x to 120 x (thus an incredible 16.5 : 1 zoom) and a capability to resolve structures down to 551 nm.

The light sources used are a tunable overhead LED lamp system, a tunable LED darkfield by Schott (the most intense darkfield we have ever worked with) and a tunable diffuse light unit.

Of course this top research gemmological microscope is equipped with polarizing filters and immersion cells for the use of various highly refractive liquids.

Research Microscope Camera Leica DFC420

The superb microscope camera has a resolution of 5 megapixel and offers capabilities unknown from other microscope cameras. The camera is aligned with the microscope which permits a continuous scale to be shown when zooming in or out with the microscope. Never again the trouble of having a photograph and not knowing the magnification used.
Below the strongly magnified image of a gas bubble in a synthetic spinel, recorded with this camera through the Leica M165C.

Advanced Spectroscopic Instruments

• PerkinElmer Spectrum BXII FTIR Spectrometer with diffuse reflectance, specular reflectance and 5x beam condenser accessories - probably the most important single instrument in our laboratory. Particularly used to identify all mineral species by specular reflectance, to identify treatments with organic materials such as resins and oils (using a beam condenser or the diffuse reflectance accessory), and to characterize diamonds (using diffuse reflectance as a beam condenser).

The three accessories used for the various applications are shown below. From left to right: fixed angle specular reflectance accessory, 5x beam condenser, diffuse reflection accessory.

• (Portable) High Resolution UV-Vis-NIR spectrometer system assembled by Gemlab, capable of low T° spectroscopy. This is the latest addition to our laboratory, and allows us to record spectra with a resolution of 0.5 nm over the range of 235 to 1050 nm with one single light source. The system includes a high resolution spectrometer with an optical resolution 0.5 nm over a range from 190 to 1100 nm.

The sample chamber is an integration sphere of 15 cm diameter which has been designed and produced by Gemlab; the sphere is covered with BaSO4 stabilized with a suitable binder. The very intense xenon light source combined with the large sample chamber allows us to record excellent spectra with the samples at room temperature or at cryogenic conditions (-196°C) within very short scanning times (commonly less than a minute). The system is also designed for very efficient reflectance spectra of opaque materials

In the image below the system can be seen with the sphere closed, and below sample spectra of two blue sapphires recorded on this system.

• Portable Vis-NIR Spectrometer Adamas SAS2000, capable of low T° spectroscopy. This instrument provides rapid good resolution UV-Vis-NIR spectra thanks to the setup of the sample chamber that is within an integration sphere. The spectrometer is especially performant for low temperature spectroscopy of coloured diamonds: we have recorded spectra at liquid nitrogen temperature for samples of 1.0 mm (0.005 ct!) up to 120 cts.

Another big advantage is the portability of the instrument - with this spectrometer we have analyzed the "Grand Condé" historical pink type IIa diamond directly in the castle "Chantilly" near Paris, France

The system additionally includes an external probe for absorption measurements in reflectance on objects that do not fit in the sample chamber or for opaque materials that cannot be analyzed in transmission, and thanks to this absolutely every gem material can be analyzed with this spectrometer.

• Portable high power - high resolution Photoluminescence/Raman spectrometer, capable of low T° spectroscopy.

This instrument uses two lasers, one 473 nm and one 532 nm laser, both extremely powerful to induce the most intense luminescence possible. The combination with an extremely sensitive high resolution spectrometer allows very rapid high resolution PL spectra even for weakest signal detection, especially useful for diamonds but also for other materials that are not affected by the intense lasers. For sensitive materials or strongly luminescent materials a lower power laser is used (see below).

As for the UV-Vis-NIR instrument this spectrometer has the big advantage of being portable.

• Portable Photoluminescence/Raman Spectrometer Adamas SAS2000, capable of low T° spectroscopy. This instrument uses a 50 mW laser (for more sensitive and strongly luminescing materials) and provides rapid good resolution PL spectra at low T°. The spectrometer is especially performant for low temperature PL spectroscopy of coloured diamonds.

As for the UV-Vis-NIR instrument this spectrometer has the big advantage of being portable - additionally to the UV-Vis-NIR spectrometer we have analyzed the "Grand Condé" historical pink type IIa diamond with this spectrometer directly in the castle "Chantilly" near Paris, France

Tunable Luminescence Imaging System with Microscope, Cooled Camera
and Very High Sensitivity Spectrometer

An instrument designed and built by Gemlab.... More to come at a later time. Below two images recorded with this system - left a neutron irradiated and annealed diamond and right the greenish blue fluorescence of an oil in an emerald.

EDXRF chemical analysis

GEMLAB owns a powerful and sensitive EDXRF system for chemical analysis, which is portable for several applications. The very compact self-designed and assembled system uses a thermoelectrically cooled detector of the latest generation and can be used under enhanced atmosphere for enhanced light element detection.

Below the EDXRF spectrum of a Mogok ruby, recorded on this system.

X-Ray imaging analysis

We are using a self-designed and built X-ray imaging system using a tunable powerful x-ray source combined with a digital x-ray detector with the highest effective resolution currently available in the market, equivalent to the highest resolution x-ray film. The "GEMLAB BlackBox " radiography system permits us to effectively distinguish between cultured and natural pearls, and to have all images stored in highest resolution on a computer. The system, if needed, could be used outside of the laboratory, since it can easily be made transportable.

The images shown were recorded with the "BlackBox" and show a near round natural saltwater pearl and a drop-shaped beaded cultured pearl.

X-Ray luminescence analysis

In several domains the luminescence of a material under X-ray excitation is observed. Our X-ray luminescence system is used for pearls, diamonds and other materials, and offers the possibilities to observe the luminescence directly via a viewing glass or via CCD camera on the computer screen.

SEM-EDX, and Micro-Raman analysis

We work with several companies and institutions to have access to these techniques that we have not (yet) directly available in our lab.

Portable Geiger Counter Alpha iX

The base device ALPHAiX is an extremely light and handy instrument for contamination measurement – as well for mobile as stationary purposes. ALPHAiX is equipped with a microprocessor controlled analysing-system which allows measurement of ALPHA-, BETA- and GAMMA-RAYs.

The device is equipped with the end-window counter tube type G that is conceived for measurement of ALPHA-, BETA- and Gamma-RAYs. It is a pure contamination counter tube which does not work as a dosimeter because its probe with its extremely high measuring sensitivity gets into the area of saturation very quickly when used with high radiation.

Concerning its energy sensitivity this portable Geiger counter is equivalent to many of the high cost laboratory counters. The energy sensitivity is 1,9 MeV for Alpha radiation, 0,09 MeV for Beta radiation, and 0,01 MeV for Gamma radiation. For example the hard-to-detect radionuclide C-14 can be determined from 1 Bq; for a run of 10 minutes the detection limits for Cs 137 are 4 Bq.

The image shows the Geiger counter with a sample a slightly radiactive parisite from the famous Muzo mine in Colombia, with a radioactivity of about 92 counts/min (with a background radioactivity in the lab of 22 cpm).