The Gemological Institute of America, or GIA, is a nonprofit institute dedicated to research and education in the field of gemmology and the jewellery arts.
Founded in 1931, GIA's mission is to protect all buyers and sellers of gemstones by setting and maintaining the standards used to evaluate gemstone quality. The Institute does so through research, gem identification, diamond grading services and a variety of educational programs.
Through its world-renowned library and subject experts, GIA acts as a resource of gem and jewellery information for the trade, the public and worldwide media outlets.
In 1953, the GIA developed its International Diamond Grading System and the Four Cs (cut, clarity, colour, and carat weight) as a standard to compare and evaluate the quality of diamonds.
Today, the institute is headquartered in Carlsbad, California and operates out of 13 countries, with 11 campuses, 9 laboratories and 4 research centres worldwide.
The GIA set the standard for diamond grading and gemmological identification, and their grading system serves as the international gem and jewellery industry's benchmark credentials.
Shape and Cutting Style: The diamond shape and cutting style.
Measurement: Lists the diamond's dimensions in millimetres.
Carat Weight: The weight of diamond listed to the nearest hundredth of a carat.
Colour Grade: A grading which assesses the absence of colour in a diamond.
Clarity Grade: Clarity grade determined under 10x magnification.
Cut Grade: A grade of cut as determined by a diamond's face-up appearance, design and craftsmanship. A cut grade is available on round diamonds graded after Jan. 1, 2006.
Finish: Grades that represent a diamond's surface and facet placement.
Polish: Rating the overall smoothness of the diamond's surface.
Symmetry: Measuring the shape, alignment and placement of the diamond's facets in relation to one another as well as the evenness of the outline.
Fluorescence: Colour, and strength of colour when diamond is viewed under UV light.
Comments: A description of additional diamond characteristics not already mentioned in the report.
Clarity Plot: A map of the approximate size, type, and position of inclusions as viewed under a microscope.
Proportion Diagram: A map of the diamond's actual proportions.