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Diamond Certificates

What's a diamond certificate? A diamond certificate is a grading report of a given diamond used to identify and determine the value of a specific stone. Grading reports help consumers to understand and select diamonds with attributes that hold the most value to them; carat, color, cut or clarity.

These reports are generated by different diamond labs around the globe. Windsor Jewelers prefers diamonds with American certificates because the diamond labs in the United States are operate under US jurisdiction and requirements. This is often why diamonds with international certificates are priced lower for what seems to be an equal certificate. It's common knowledge that US labs have the highest standard for grading diamonds and we want the consumer to know exactly what they are purchasing.

Windsor Jewelers has certified GIA and AGS gemologists on staff right here in Augusta, Ga. We've listed the three main diamond labs that we work with, though most of our stones are either GIA or AGS.


Gemological Institue of America was founded as an institute of research and knowledge for the diamond and gemstone trade. GIA is credited with developing the system of the "4 C's"; Color, Cut, Carat and Clarity. GIA is known as the world's standard for color and clarity.


American Gem Society was founded as an organization of retail jewelers bound by the highest code of ethics in the industry. AGS is known as the world's standard for precise measurements of cuts and considered one of the top two grading labs in the world (GIA being the other).


European Gemological Laboratory - United States of America. EGL-USA has taken incredible strides to separate itself from the scrutiny of internationally graded diamonds by demonstrating its dedication to the American standard of diamond certificates. They are based in the USA.