Until the middle of the twentieth century, there was no agreed-upon standard by which diamonds could be judged. GIA created the first, and now globally accepted standard for describing diamonds: Color, Clarity, Cut, and Carat Weight. Today, the 4C's of Diamond Quality is the universal method for assessing the quality of any diamond, anywhere in the world.

The creation of the Diamond 4C's meant two very important things: Diamond quality could be communicated in a universal language, and diamond customers could now know exactly what they were about to purchase.