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Gemstone characteristics and constants used for identification
Preparation and handling of gemstones
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absorption adjusted alexandrite apatite bands beam birefringence blue calibrated carat Chapter CIBJO colour grading corundum critical angle crystal dark-field diamond grading diamond simulants dichroscope diffraction grating dispersion Eickhorst electron emerald equipment eyepiece field of view fitted fluorescence garnet Gem Instruments gem minerals Gem Testing Gemmological Instruments Ltd gemmologist gemstone Gilson glass hand loupe Hanneman hardness heavy liquids identified illumination incident light inclusions infra-red Journal of Gemmology Kriiss laboratory lapis lens light guide light source light-field lines luminescence lustre LW ultra-violet magnification measured method microscope natural opal optical Orthorhombic phosphorescence pleochroism polariscope polarising filter polished diamonds prism produced quartz range Rayner rays reading refractive index refractometer rotated ruby sample sapphires simulants slit specific gravity specimen spectra spectrometer spectroscope spectrum spinel stereo zoom stone holder strontium titanate surface synthetic spinel table facet tube tweezers ultra-violet lamps ultrasonic unit visible wavelength wavelength scale weight X-ray yellow zircon