7 QUALITIES OF PEARLS
Of the seven pearl value factors, luster might be the most important. Luster is what gives a natural or cultured pearl its unique beauty. Pearls with high luster have sharp bright reflections on the surface. Different pearl varieties have different standards for luster.
If surface characteristics are numerous or severe, they can affect the durability of the pearl and severely depress its value. Surface characteristics have less effect on the pearl’s beauty and value if they are few in number, or if they are minor enough to be hidden by a drill-hole or mounting.
Pearls come in eight basic shapes: round, semi-round, button, drop, pear, oval, baroque, and circled. Perfectly spherical pearls and symmetrical drops are the most valued. There are exceptions, though. Well-formed pear, oval, or baroque cultured pearls are also prized by pearl lovers.
Pearl body colors vary by variety. Although white and black are traditional, unusual colors are becoming more popular. Overtones in a pearl’s luster and the rainbow iridescence known as orient also add to the color of a pearl.
Luster and nacre quality are closely related. If the nucleus is visible under the nacre, or if the pearl has a dull, chalky appearance, you can assume that the nacre is thin. This affects the luster as well as the durability of the pearl. Nacre thickness is evaluated to make sure that cultured pearls are durable as well as beautiful.
In general, the larger the pearl, the more valuable it is. Different varieties come in different sizes: South Sea cultured pearls are the largest.
Jewelry designers sometimes deliberately mix colors, shapes, and sizes for unique effects, but for most pearl strands, earrings, or other multiple-pearl jewelry, the pearls should match in all the quality factors.