A Pearl is produced by a small foreign object that becomes trapped in a freshwater mollusk or a saltwater oyster. The foreign object becomes an irritant to the mollusk. To protect itself from the irritant the mollusk coats the foreign object with "nacre". The crystalline structure of the nacre produces the reflective and refractive "Rainbow Effect" on the surface of the pearl. The longer the foreign object remains in the mollies the thicker the nacre becomes and more "Rainbow Effect" the pearl will have. The pearl grows in diameter through this layering of nacre.
Natural Pearls form in nature without the aid or intervention of man. The foreign object happens to enter the mollusk by accident. Cultured Pearls are created by man implanting the foreign object in the mollusk. Generally the implant is a mother-of-pearl bead. This bead forms the nucleus of the Pearl. Natural Pearls generally have a much thicker layering of nacre than Cultured Pearls and are less uniform in shape and color. Cultured Pearls are raised in "Farms" in the Ocean, Freshwater Lakes and Rivers. The Pearl Farmer tries to control food, water and pollutants in an attempt to control color and quality. Matched sets of Cultured Pearls are much easier to create because there are so many produced. Matching Natural Pearls to make a set is much harder due to the limited number found each year.
There are 5 basic issues for evaluating Pearls.
1. Luster and Iridescence
The Luster is the ability to reflect an image from the surface of the Pearl. The Iridescence is the refractive "Rainbow Effect" produced by the layers of nacre. The greater the Luster and Iridescence the more valuable the Pearls.
Color evaluation consists of 2 issues, Basic Color and Overtone. Basic Color (also called Body Color) is the actual color of the Pearl's Body. Basic Colors are White, Pink, Blue, Gray and Black. Many variations of these colors are available and may be enhanced by dyeing or irradiation. Overtone is the Tint or secondary color. White Pearls may have a Rose Colored or Pink Overtone. These are the most valuable. As the Overtone shifts to Cream and then Green the value of the Pearls lessens.
3. Surface Texture
The smoother the surface of the Pearl the better the quality. Blisters or discolored spots reduce the value of the Pearls.
Saltwater Pearls are grouped in 3 basic shapes Round, Semi-Round and Baroque. Round are the most valuable. Perfectly round Pearls are difficult to find. Semi-Round Pearls may be shaped like Buttons, Pears or simply not round. They are smooth but not truly round. They or more valuable than Baroque but less valuable than Round. Baroque have irregular shapes including bumps or arms.
Freshwater Pearls may be shaped like BIWAs, Striped BIWAs (shaped like Root Beer Barrels), Rice, Buttons, Pears and Potatoes. The important thing to remember is the Pearls should be similar in shape from one end of the strand to the other.
Size is evaluated in millimeters(mm). 2mm is a small Pearl. 8mm and larger is considered vary large. Freshwater Pearls are measured by length and width because they are not round. Saltwater Pearl sizes may be stated as a range (6 to 6.5mm). Generally the larger the size the more expensive the Pearl. Prices increase dramatically above 7.5mm.
Most recent revision: October 17, 2005