gemological

Gemological is an adjective relating to gemology, the science that studies gemstones. Gemology encompasses the identification, characterization, origin, treatment, grading, and certification of both natural and synthetic stones, as well as the evaluation of simulants and composites. The term gemological is used to describe stones, reports, methods, or practices that pertain to gemstones or the practice of gemology.

Professionals in gemology, known as gemologists, determine the species and variety of stones, assess authenticity, detect treatments (such as heating, irradiation, fracture filling, diffusion), and distinguish natural stones from lab-grown or synthetic alternatives. They may also evaluate provenance and distribution, though origin determinations can be uncertain and debated. Gemological reports are used by jewelers, insurers, collectors, and courts.

Common techniques include measuring refractive index and birefringence, determining specific gravity, assessing pleochroism, relief, and inclusions, and evaluating luster. Instrumentation typically includes a stereomicroscope for inclusions, a refractometer, polariscope, polarized light microscope, spectroscope, and UV light. Advanced analyses employ Raman spectroscopy, infrared spectroscopy, X-ray diffraction, and other non-destructive methods.

Organizations such as the Gemological Institute of America (GIA), the International Gemological Institute (IGI), and the American Gem Society (AGS) provide education, grading systems, and gemstone certificates that document species, variety, carat weight, treatments, and sometimes origin. The field continues to evolve with the study of laboratory-grown stones, disclosure of treatments, and standardized grading practices to support appraisal, commerce, and conservation of gem materials.