360-degree video of the Motswedi diamond.

A black opal cabochon set in a ring displays vivid orange play-of-color.

Presents the first scientific and historical study conducted on the 2.33 ct Winston Red, the fifth-largest known Fancy red diamond in existence.

Investigation in the Carlsbad laboratory reveals a pearl submission is not mabe as initially believed.

The Bangkok laboratory studies 35 loose non-nacreous pearls from a wide range of marine mollusk species.

Examination of a gigantic South Sea bead cultured pearl reveals an intriguing internal structure.

Archival research and gemological characterization reveal the geographic origin of two emeralds set in a pendant linked to Catherine de’ Medici, Queen of France from 1547 to 1559.

Learn about the principles, mechanisms, and characteristics of luminescence that create the impressive and memorable glow of gemstones.

Gemology has become a highly technical field employing analytical instruments for gem testing, driven by the need to address increasingly complex identification challenges in the marketplace.

Photoluminescence spectroscopy examines how gemstones absorb and emit light, uncovering crucial details about their identity and color origin through the detection of microscopic defects and impurities.

Infrared spectroscopy, specifically FTIR analysis, measures atomic vibrations to determine identity, cause of color, and potential treatments by analyzing how a gemstone absorbs infrared light.

GIA ensures accurate gemological measurements across its global laboratories through rigorous metrology practices, including systematic instrument calibration, validation from traceable standards, and continuous monitoring by trained staff to maintain precision and consistency.

UV-Vis-NIR spectroscopy measures how gemstones absorb and interact with light across the ultraviolet, visible, and near-infrared ranges, revealing crucial information about their composition, origin, and potential treatments.

GIA’s laboratories use advanced instrumentation and research to deliver accurate grading, identification, and origin determination for natural and laboratory-grown diamonds, colored stones, and pearls.

Photoluminescence imaging, which analyzes how gemstones glow under ultraviolet light, is an important analytical tool for detecting impurities, natural versus synthetic gems, and treatments through the observation of fluorescence and phosphorescence patterns.

X-ray imaging techniques revolutionized pearl testing by enabling gemologists to distinguish natural from cultured pearls through detailed visualization of their internal structures, evolving from film-based systems in the early 1900s to today’s sophisticated digital equipment.

The primary chemical analysis methods applied in gemology are XRF, which uses X-ray emissions for nondestructive testing, and LA-ICP-MS, which provides detailed analysis and greater sensitivity. LA-ICP-MS has become essential for origin determination and treatment detection.

Raman spectroscopy and XRD techniques are used to identify gemstone species through their atomic-scale structures, with Raman spectroscopy analyzing inelastic light scattering from crystal lattice vibrations and XRD examining X-ray interference patterns from atomic layers.

An overview of the Winter 2024 Gems & Gemology content.

Methods, Treatments, and Identification