Every diamond is unique, and there are a several factors that define a diamond. Focus on those factors most important to you, and choose a diamond that satisfies your individual standards for beauty and value. GIA created the first, and now globally accepted standard for describing diamonds: Color, Clarity, Cut, and Carat Weight. Today, the 4Cs of Diamond Quality is the universal method for assessing the quality of any diamond, anywhere in the world. Understand your diamonds better with Purpletabâs Diamonds Forever.