Established in 1931 by Robert Shipley, The Gemological Institute of America (GIA) is the one of the world’s biggest, most sophisticated, and extraordinarily consistent Diamond Grading Laboratory!
The G.I.A. headquarters and main campus is located in the city of Carlsbad, in California, with a satellite campus located in New York and some other major cities in the World.
A GIA Diamond Grading Report isn't an appraisal but a scientific blueprint of your stone's exact qualities. The most widely used and trusted means of verifying a diamond's quality and providing positive identification is a GIA Diamond Grading Report.
A GIA grading report provides an expert analysis of a diamond's quality based upon the "4Cs" of diamond grading: carat, color, cut and clarity. Because GIA is not affiliated with any commercial enterprise, impartial and accurate analysis of a diamond's quality and value is assured.
The GIA Laboratory issues diamond grading reports for loose, natural diamonds in the D-Z color range that weigh 0.15 carats or more. GIA Diamond Grading Reports are not issued for synthetics, simulants, mounted diamonds or those that have undergone unstable treatments, such as fracture filling or coating. And while reports may be issued for diamonds that have been laser drilled or HPHT processed, these stable treatments are prominently disclosed on the report.
GIA diamond grading reports always include the date of issue, report number and laser registry if the diamond has been laser inscribed. A Diamond Grading Report documents the specific characteristics of a diamond.
Details Documented in the Diamond Grading Report
Table: Located at the top of the diamond, the table is the largest facet of a diamond.
Girdle: Range of girdle thickness.
The G.I.A. headquarters and main campus is located in the city of Carlsbad, in California, with a satellite campus located in New York and some other major cities in the World.
A GIA grading report provides an expert analysis of a diamond's quality based upon the "4Cs" of diamond grading: carat, color, cut and clarity. Because GIA is not affiliated with any commercial enterprise, impartial and accurate analysis of a diamond's quality and value is assured.
The GIA Laboratory issues diamond grading reports for loose, natural diamonds in the D-Z color range that weigh 0.15 carats or more. GIA Diamond Grading Reports are not issued for synthetics, simulants, mounted diamonds or those that have undergone unstable treatments, such as fracture filling or coating. And while reports may be issued for diamonds that have been laser drilled or HPHT processed, these stable treatments are prominently disclosed on the report.
GIA diamond grading reports always include the date of issue, report number and laser registry if the diamond has been laser inscribed. A Diamond Grading Report documents the specific characteristics of a diamond.
Details Documented in the Diamond Grading Report
- Report number: A unique number assigned to a diamond and registered in GIA's global database.
- Shape and Cutting Style: The diamond shape and cutting style.
- Measurements: This includes dimensions of the diamond as minimum diameter - maximum diameter x depth (for round diamonds) or length x width x depth (for fancy shapes).
- Carat Weight: The weight of diamond listed to the nearest hundredth of a carat.
- Proportions: Various characteristics of the diamond are underlined here. These include:
Table: Located at the top of the diamond, the table is the largest facet of a diamond.
Girdle: Range of girdle thickness.
- Finish: Grades that represent a diamond's surface and facet placement.
- Culet: Appearance, or lack thereof, of the culet facet.
- Polish: Rating the overall smoothness of the diamond's surface.
- Proportion Diagram: A map of the diamond's actual proportions.
- Reference Diagram: This approximates the shape and cutting style of the diamond. It also indicates clarity characteristics in the stone. Key to symbols used on the diagram is also provided.
- Color Grade: A grading which assesses the absence of color 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.
- 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: Color, and strength of color 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.
- Grading scales: GIA grading scales on color and clarity are provided. The clarity grade provides grading on a scale which lists from flawless to included. Color grading is provided on a scale from colorless to light yellow, brown or gray. Color grading is achieved by comparing stones to master comparison diamonds.
- Security features: To ensure that the certificate is secure and cannot be forged, GIA certificates come with certain security features. These include hologram, watermark, an embossed seal, chemical sensitivity feature, microprint lines and security screen are also provided to ensure that the certificate is original.
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