Guide to culture pearl quality When you shop to buy pearls The gift of a pearl necklace often commemorates a wedding, anniversary, or other special occasion. With all the beautiful choices of pearl jewelry, an educated decision is the key to a successful pearl purchase. Unlike diamonds, there is no standard grading system for pearls. Some companies such as Mikkimoto use a grading system of A, A+, AA, AAA, etc. This can get complicated and hard to interpret, not to mention that this is but one of many systems. When you look to buy pearls, information on pearl luster, pearl color, pearl shape, pearl size and the pearls surface is the key to knowing what to look for when you go out to buy a pearl necklace, pearl bracelet or pearl earrings. Pearl color -- is the dominant impression of the color of the pearl. These can range from white and cream to pink, gray and black, with many colors in between. No one color is better than the next and your jeweler should be able to tell you which color compliments your skin color. Overtone -- is the secondary color which appears to be superimposed on the body of the pearl and is displayed when the pearl is moved under a direct light source. The most desirable overtone in white pearls is pink and in black pearls, green. Pearl Luster -- is the quality and quantity of light reflected from the surface of the pearl. This is dependent on the fineness of the crystals that make up its nacre. Finer nacre is produced in colder waters, such as in Japan. Pearl Shape -- is the shape of the pearl. Perfectly round or spherical pearls are more valuable than odd shapes known as Baroch or free form. Pearl surface -- is the evaluation of the surface characteristics such as bumps, dark spots and cracks. Skilled pearl graders note the size, number, location and visibility of these characteristics. The more free from blemishes, the more valuable the pearl. Pearl Size -- the larger the pearl, the more its value is increased.