Perfect shining spheres. Lustrous baroque forms. Seductive strands, warm to the touch. Pearls are simply and purely organic.
Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of colors. The most familiar colors are white and cream (a light yellowish brown). Black, gray, and silver are also fairly common, but the palette of pearl colors extends to every hue. The main color, or bodycolor, is often modified by additional colors called overtones, which are typically pink (sometimes called rosé), green, purple, or blue. Some pearls also show the iridescent phenomenon known as orient.
Cultured pearls are popular for bead necklaces and bracelets, or mounted in solitaires, pairs, or clusters for use in earrings, rings, and pendants. Larger pearls with unusual shapes are popular with creative jewelry designers.
Pearl—natural or cultured—is a US birthstone for June, together with alexandrite and moonstone.
Natural pearls form in the bodies, or mantle tissue, of certain mollusks, usually around a microscopic irritant, and always without human help of any kind.
The growth of cultured pearls requires human intervention and care. Today, most of the mollusks used in the culturing process are raised specifically for that purpose, although some wild mollusks are still collected and used.
o begin the process, a skilled technician takes mantle tissue from a sacrificed mollusk of the same species and inserts a shell bead along with a small piece of mantle tissue into a host mollusk’s gonad, or several pieces of mantle tissue without beads into a host mollusk’s mantle. If a bead is used, the mantle tissue grows and forms a sac around it and secretes nacre inward and onto the bead to eventually form a cultured pearl. If no bead is used, nacre forms around the individual implanted mantle tissue pieces. Workers tend the mollusks until the cultured pearls are harvested.
There are four major types of cultured whole pearls:
Akoya—This type is most familiar to many jewelry customers. Japan and China both produce saltwater akoya cultured pearls.
South Sea—Australia, Indonesia, and the Philippines are leading sources of these saltwater cultured pearls.
Tahitian—Cultivated primarily around the islands of French Polynesia (the most familiar of these is Tahiti), these saltwater cultured pearls usually range from white to black.
Freshwater—These are usually cultured in freshwater lakes and ponds. They’re produced in a wide range of sizes, shapes, and colors. China and the US are the leading sources.
BIRTHSTONES & ANNIVERSARIES
Pearl is the birthstone for June and the gem of the third and thirtieth anniversaries.
WHY WE LOVE THIS GEMSTONE
LUSTER: Luster results from reflection of light rays off the pearl’s surface, and from concentric inner layers of nacre, like light bouncing off a convex mirror.
IMITATIONS: Imitation pearls are smooth when rubbed against your teeth, while natural or cultured pearls have a slightly rough texture.
NATURAL PEARLS: Natural pearls can be separated from cultured pearls by taking X-rays to reveal their inner structures.
MINERAL: Calcium Carbonate
COLOR: White, black, gray, yellow, orange, pink, lavender, green, blue
REFRACTIVE INDEX: 1.52-1.69
SPECIFIC GRAVITY: 2.60-2.85
MOHS HARDNESS: 2.5-3.0