Diamond Buying and the Four Cs, Part 1: Diamond Carat Weight

A Brief History of the GIA Diamond Grading System

Before the Gemological Institute of America (GIA) developed the Four Cs system in 1953, diamond grading was quite subjective. For example, the finest diamonds received designations such as “gems of the first water.” Lesser diamonds were known as diamonds of the “second” and “third water.” When using these terms, Arab traders most likely referred to a combination of clarity, brilliance, and colorlessness. The finest diamonds were supposed to be limpid, like water, and brilliant and lively, as if a river moved through the stone.

The first attempts to create more objective standards gave diamonds grades such as A, AA, AAA, and even AAA+. However, there was no consensus on how to classify diamonds into these groups. This state of affairs caused confusing among diamond buying consumers, as retailers used these grades to market their stones rather than describe them accurately.

Robert M. Shipley, the jeweler and educator who founded the GIA, developed the Four Cs system. Indian traders had already used three of the properties — color, clarity and carat — for thousands of years. Shipley went into greater depth for each property and also set the criteria for cut.

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Phoebe Shang, GG

A gem lover and writer, Phoebe holds a graduate gemologist degree from the Gemological Institute of America and masters in writing from Columbia University. She got her start in gemology translating and editing Colored Stone and Mineral Highlights for a professor based in Shanghai. Whether in LA, Taipei, or New York, Phoebe spends her time searching for gems to design and being lost in good books.

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