While a EGL diamond certification is the norm in Europe, a GIA (Gemological Institute of America) diamond certification report is the accepted report for diamonds in the USA.
The GIA was established in 1931 to protect purchasers of gemstones by providing the necessary educational material, laboratory research and other resources needed to assist purchasers in their decision as to buying various gemstones. The majority of gemstones of course are diamonds.
Although the GIA provide a variety of services, they are most well know for the certificates they provide which offer substantiation of the qualities and characteristics of gemstones they have on file in their database.
Take a diamond for example. A diamond, or other gemstone, submitted for grading goes through a rigorous process including being weighed with an electronic micro-balance to capture the weight to the fifth decimal place. Being optically measured to determine the exact proportions, measurements and facet angles.
Color is graded in a standardized viewing environment. A number of professional color graders are used who offer their independent opinions into the system. The color grade of the diamond is determined when sufficient color graders agree on the specific color.
The import grading of clarity and finish is done with a 10x magnification under standard viewing conditions. During this phase the grader examines the diamond, locating and recording any treatments such as fractures, fracture filling and laser drilling.
The grader gives his opinion of the diamonds clarity polish and symmetry. He then plots out the clarity characteristics on a diagram that most represents the diamond shape, such as a princess or oval cut for example. GIA keeps a database of hundreds of diagrams to choose from.This attention to detail continues with a second grader closely examining the diamond and going through the same process completing all the prior grading step again, entering an opinion on the clarity, polish and symmetry.
Additional quality assurance processes are performed and the grading might even be reviewed by more experienced graders and gemologists.Once there is agreement among the graders then the grading results are finalized.
A Certified Diamond Reports should provide the following information:
Shape
Measurements
Weight
Depth Percentage
Table Percentage
Girdle Thickness
Culet Size
Polish
Symmetry
Clarity Grade
Color Grade
Fluorescence
Comments about Diamond
Plot of Internal and External Inclusions
During the grading process anonymity is preserved with all references to the owner of the gemstone removed and replaced by a bar-coded label with a unique internal identification number used to track it throughout the process. The diamond is kept in a custom designed transparent storage case.
Of course there is a cost to all of this. The fee depends basically upon the weight of the diamond and ranges, in US dollar terms from just over 50 dollars for the smallest up to 0.15 of a carat to over 3000 US dollars for a 40 carat colored diamond. One can find a fee schedule on the GIA website.
The GIA has offices and laboratories word wide. As well as the US there are laboratories in the UK, Europe, South Africa and Asia.
With any diamond, large or small, to get a good diamond price or to have some idea what the price of a diamond should be getting a GIA report is most important and well worth the few dollars it costs. It is also important for insurance purposes as well as potential sales.
A GIA Diamond Certification is most important therefore in establishing the authenticity of a diamond and its potential value when it comes to the diamond price.
One should check to ensure the jeweler you use has certficates from eithwer GIA or another reputable laboratory. James Allen is an example of a professional jewelers who ensure that independent certificates are provided where required for their diamonds.
