Shree Radhe Krishna International Gems Testing Laboratory

Ultra Violet- Visible- Near Infrared spectrometer A gemmologist commonly uses hand-held or desk model spectroscopes to observe the absorption features of a gemstone, in the visible region 400 - 700 nm. However, human eyes are not capable to observe very minute features, which are missed to be seen and hence, may affect the conclusions and overall results. Therefore, spectrometers or spectrophotometers may be used, which are capable to analyse the sample in detail and registers the absorption features in the form of a graph. These spectrometers not only analyses the sample within 400 - 700 nm range, but much beyond this, from 175 nm in the ultra violet region up to 3300 nm in near-infra red region. This however depends on the type and grade of instrument and accordingly, the spectrometers can be termed as UV-Vis or UV-Vis-NIR spectrometers.  In UV-Vis-NIR spectrometry, the scale or position of absorptions is expressed in wavelength nanometers (nm) as against the IR or Raman spectr...

DIAMONDVIEW DiamondView as the name suggests, was developed by the Diamond Trading Company to screen diamonds for determination of natural and synthetic origin. The instrument basically is an imaging system, which uses the short-wave ultraviolet light below ~225 nm. The sample is targeted with the ultraviolet light and fluorescent reactions are observed through a CCD camera, which captures the fluorescent reactions and display them on the monitor through software. DiamondView not only assists in observing the fluorescence of the sample, but also its growth pattern as the CCD camera magnifies the sample, enabling to view the structure properly, against a gemmological ultraviolet lamp. The fluorescence image produced is of the surface or sub-surface up to few microns. It also assists in observing 'phosphorescence' of a sample. The fluorescent reactions not only indicate the presence of impurities but also the conditions in which a gem has formed. Therefore, the fluorescence i...

FOURIER TRANSFORM INFRA-RED (FTIR) SPECTROMETER An infrared spectrum presents a fingerprint of a sample with absorption peaks corresponding to the vibrations between the bonds of the atoms, constituting the material. Bonds in the molecules absorb infra red rays at one or more specific frequencies and produce vibrational characteristic of molecules in one of the three major parts of the infra red region, namely, Near Infrared (NIR), Mid Infrared (MIR) and Far Infrared (FIR). Organic compounds, H2O and CO2 may provide characteristic information in the Near to Mid Infrared region, while Far Infrared region display lattice vibrations, allowing identification of the mineral group (such as silicate, carbonate, sulfide, etc). However, this region is used only occasionally, as the molecules in minerals are too dense, and seldom display characteristic peaks, in routine measurement techniques.  FTIR or Fourier Transform Infra Red spectrometer is the instrument which measures all of the ...

Microscopy The microscope remains the most important tool in gem identification. A thorough and detailed analysis reveals a lot of information about a gem - it has a story to tell - about its origin - the depth within the earth's crust, the temperature and pressure conditions, the chemical environment in which it has formed, and much more. Observation of internal features is still the most valuable technique in identifying the nature of a gem. In some cases, the features are so characteristic, that they not only tell the identity of a gem, but also its origin. Microscopy remains the core of any gemmological study and complements 'the many' spectroscopic analytical tools, in determining the nature, whether natural or synthetic and the type and degree of treatments performed. At Shree Radhe Krishna International Gems Testing Laboratory, every analysis is started with a detailed microscopic observation.