Spectroscopy is the science of analyzing the way light breaks into its component colors. By analyzing these different colors, we are able to determine a number of very specific properties in the gemstone being studied. Depending on the type of spectrometer we use, the varying test results will help determine not only the chemical makeup of the gemstone itself, but specifically, where it gets its color from, whether the gemstone is synthetic or natural, if it has been treated, and even what part of the world it is from.
(See below for varieties of Spectrometers)
Using an Ultra Violet-Visible (UV-VIS) spectrometer, we are measuring the absorption and reflectance of the material being tested within the Ultraviolet to the Visible range of the electromagnetic spectrum. This can help determine natural or treated color in diamonds, country of origin in gemstones and help separate a synthetic(man-made) gemstone from its natural counterpart.
Similar to a UV-VIS spectrometer, Fourier Transform Infrared (FT-IR) spectrometers also measure absorption and reflectance of the material being tested. Unlike UV-VIS though, FT-IR measures in the infrared region of the electromagnetic spectrum opposed to the Ultra Violet to Visible region. FT-IR spectrums can detect polymers, resins, and oils used for treating emeralds or jade. It can even help determine a heat treated ruby or sapphire by simply measuring the amount of H20 (water) present in the gemstone.
Probably the most complex of the spectrometers; a Raman spectrometer has a very broad range of use in gemology. Identification of gemstones is number one because of each gemstone’s characteristic Raman spectra, which helps identify nearly all gemstones with precision. When combined with a microscope, the laser used to gain a spectral reading can be positioned and focused to an internal component of a gemstone such as an inclusion to help identify the nature of the inclusion trapped inside. Being able to identify the smallest of characteristics inside a gemstone can provide valuable information about the gemstone itself.
Energy Dispersive X-Ray Fluorescence (EDXRF) in the most basic sense helps determine not only what chemical elements are present in a gemstone, but also how much Doing so allows us to detect transition elements that are responsible for the gemstone’s color and potential treatments that may have been applied, such as Chromium in Colombian Emeralds and Copper in Paraiba Tourmaline.