Global gold standard
The GIA standard: history, science & report anatomy.
Established in 1931 by Robert M. Shipley, the Gemological Institute of America is a non-profit institute widely considered the world’s foremost authority on gemology.
The origin of the modern diamond language
Before GIA, diamond grading was inconsistent. Terms like “blue-white”, “commercial quality” and “gem grade” were subjective and easily manipulated. GIA introduced the standardised D-to-Z colour scale — deliberately starting at D to break from ambiguous A/B/C systems — and the standardised clarity hierarchy.
Anatomy of a GIA dossier
GIA report number
A unique 10-digit identifier permanently logged in GIA’s global database.
Shape and cutting style
Exact geometric classification, e.g. Round Brilliant, Cushion Modified.
Carat weight & dimensions
Calibrated to 1/1000th carat, recorded to two decimals with three-dimensional caliper measurements.
Proportions & facet angles
Crown angle, pavilion depth, table percentage and culet size.
Browse GIA-certified natural diamonds.
Every listing links to its live official report.