Instrumentation

The DiamondView^© exposes gemstones to high-energy ultraviolet radiation, then captures real-time images of the resultant fluorescence and/or phosphorescence colors and distribution patterns. With this instrument, the gem sample can be rotated to allow the operator to observe any changes in the fluorescence colors or patterns. These images are useful in separating natural from synthetic diamonds, as well as for identifying other gem materials.

This equipment is used to produce real-time, high-resolution digital X-ray images of the internal structure of natural and cultured pearls to help differentiate them.

The Fourier-transform infrared (FTIR) spectrometer records infrared spectra either by reflecting the incident energy off the surface of a gem, or by transmitting the energy through it. Infrared spectroscopy is particularly valuable for detecting the presence of foreign substances in treated gem materials, such as oils or resins in a fracture-filled emerald. A number of synthetic gem materials can be distinguished from their natural counterparts by differences in their infrared spectra. Type I and type II diamonds can also be recognized.

The Hitachi UV-Visible-NIR instrument is used to collect absorption and reflectance spectra from colored gemstones and pearls, which help determine geographic origin and detect treatments.

The Raman instrument with multiple-laser excitation options has a wide range of gemological applications, including identification of gemstones based on their distinctive Raman spectra. Because the instrument is combined with an optical microscope, the incident laser light beam can be positioned on an internal mineral inclusion to identify its nature. Identifying mineral inclusions can provide valuable information on the nature of the host gemstone itself. Photoluminescence spectra collected with this equipment at low (liquid nitrogen) temperatures are particularly useful in detecting diamond color treatments.

A laser ablation–inductively coupled plasma–mass spectrometer (LA-ICP-MS) allows for quantitative measurement of the trace-element chemical composition of gem materials. A laser is used to remove tiny particles of material from the surface of a gemstone. These are transported by a gas into a high-temperature plasma, where they are broken down into individual ions that can be identified by a mass spectrometer. LA-ICP-MS is capable of detecting almost all natural elements to very low concentrations, which can help determine a gem’s geographic source or trace elements that suggest laboratory synthesis or treatment.

This instrument collects fluorescence emission or excitation spectra over a wide range of excitation wavelengths. The resulting luminescence spectra can help characterize and distinguish certain natural, synthetic and treated gem materials.

This UV-visible-near-infrared instrument is used to collect absorption and reflectance spectra from colored gemstones and pearls to help determine geographic origin and detect treatments.

The energy-dispersive X-ray fluorescence (EDXRF) system is used for the qualitative determination of a gemstone’s chemical composition.  An X-ray beam illuminates the sample, and this incident energy causes the material to emit X-rays that are characteristic of the major and minor chemical elements in the gem. EDXRF is particularly helpful in detecting transition metal elements, which are the coloring agents in many gem materials, as well as other elements that are evidence of certain treatment processes.

The Unicam UV-visible-NIR instrument is used to collect high-resolution absorption spectra from colored gemstones and diamonds. With the cryogenic sample accessory, it is particularly useful for identifying treatments in colored diamonds.