Pearl quality

Pearl quality is assessed in the following way: A grade pearls are officially known as 90% perfect with great luster and no more than two imperfections within the 10% of allotted surface. B grade pearls must have great luster as well but tolerance swings to 70% of the total surface being without flaws. C grade pearls must have decent luster with 40% of the surface being clean. C grade pearls often find themselves in strands as drilling from one side to the other tends to conceal what can't be hidden in pendant or ring settings. D grade pearls are more characterized by their consummate flaws than anything else. Luster is variable.