Diamonds

The Gemological Institute of America (GIA) is one of the premier authorities used to grade loose diamonds, and thus assure consumers of standards recognized by diamond merchants worldwide. The GIA was founded in Los Angeles in 1931 by Robert M. Shipley who realized the value of professional standards in training and business practice. The Institute (and later a guild) was founded with the purpose of encouraging gemological learning and research. By using the knowledge acquired by the Institute, Shipley hoped to encourage the public trust in gems and jewelry in America.

On January 1, 2006, the GIA revealed updated versions of its famous grading reports. Each diamond is evaluated by a certified gemologist who spends 30 to 60 minutes evaluating each stone under a microscope to determine its proportions, color, symmetry, fluorescence, cut, clarity and carat weight. The gemologist then issues a diamond dossier or grading report that accompanies the diamond in the future. Customers should always insist on the grading report from an independent laboratory, such as the GIA, as part of their purchase.

The new reports have fresh cover designs, are newly formatted to make them easier to read and contain informative descriptions of the Four Cs: Cut, Clarity, Color and Carat-weight. The cut, which ideally optimizes the diamond in such a way that its fire and brilliance are maximized, is the single most important factor in determining the beauty of a diamond.

Clarity rates the flaws or inclusions caused by carbon deposits or feather cracks created while the diamond is formed. Color in diamonds is not valued; indeed the highest rating of D indicates that a diamond is absolutely colorless.

Carat-weigh ranges from sand (less than 0.1 carat) to more than one carat. A carat is a unit of measurement. One carat equals 200 milligrams or 0.2 grams. A 1.25 carat diamond weighs 250 milligrams. Dealers typically recommend that an engagement ring, for example, be of at least 1 carat, good color (D, E, F-colorless-or G, H, I, or J-near colorless), and a clarity grade of S11, S12 or higher. Sometimes, it is necessary to make trade-offs on one feature or another because of budget concerns.

Typical diamonds from GIA contain a GIA laser inscription registry number, information on the shape and cutting style with a profile showing the proportions of the stone, measurements, carat weight, color grade, clarity grade, and additional grading information. The report is imprinted on security paper with a hologram, security screen and microprint lines to insure the complete integrity of the report. But, most importantly, for the customer, since the GIA's report is rendered by an independent authority, it carries the assurance of impartial diamond graders you can trust.