Gemology

Gemology is the science dealing with natural and artificial gemstones, their physical and chemical properties, identification, valuation, and care. It overlaps with mineralogy, crystallography, and jewelry technology. Practitioners, known as gemologists, assess gems for authenticity, source, treatment, and quality.

The field covers a wide range of materials, including diamonds, colored stones such as rubies, sapphires, emeralds, and softer gemstones, as well as crystal and organics like opals and pearls. It also includes synthetic stones and simulants, and the study of gem sources and formation. Grading and appraisal are used by dealers, collectors, and institutions.

Core methods include non-destructive testing and microscopy. Tools include a refractometer for refractive index, spectroscope for spectral lines, polariscope for pleochroism and birefringence, dichroscope, UV lamp for fluorescence, a loupe, and a gemological microscope. Inclusions and external features help determine origin and individuality. Treatments such as heat, irradiation, diffusion, and fracture filling are identified and disclosed.

Certification and standards are provided by laboratories such as GIA, AGTA, IGI, and SSEF. Diamonds are commonly graded by the 4 Cs: color, clarity, cut, and carat weight; other stones are evaluated by color quality, clarity, cut, and consistency with species-specific criteria. Gemology education ranges from certificates to advanced degrees, guiding appraisal, authentication, and material research.