The World's Largest Pearl Information Source

Natural Pearls

Pearls have been prized for their beauty and rarity for more than four thousand years. From ancient China, India, and Egypt, to Imperial Rome, to the Arab world, to Native American tribes, cultures from around the world and throughout recorded history have valued pearls longer than any other gem.

Pearls are the only gemstones grown inside of a living organism. Pearls are formed within oysters or mollusks when a foreign substance (most often a parasite - not a grain of sand) invades the shell of the mollusk and enters the soft mantle tissue. In response to the irritation, the mantle's epithelial cells form a sac (known as a pearl sac) which secretes a crystalline substance called nacre, the same substance which makes up the interior of a mollusk's shell, which builds up in layers around the irritant, forming a pearl.

There are approximately 8,000 different species of bi-valve mollusks, of which only about 20 are capable of consistently producing pearls. Natural pearls are extremely rare. Because the layers of nacre tend to maintain the irregular shape of the original irritant, natural pearls which are round or spherical in shape are even more rare. Most natural pearls are irregularly shaped.

In a completely natural state, only a very small percentage of mollusks will ever produce a pearl and only a few of them will develop a desirable size, shape, and color; only a small fraction of those will be harvested by humans. It is commonly assumed that one in ten thousand mollusks naturally produce gem quality pearls. Obviously, if we relied only on nature, ownership of pearls would still be relegated to the wealthiest and pearl producing mollusks would be on the brink of extinction due to over-harvest. As pearls have been prized for thousands of years, this need has led to the development of cultured pearls.

Cultured Pearls

In the early part of the 20th century, Japanese researchers discovered a method of producing pearls artificially. Essentially, the method involves inserting a foreign substance, or nucleus, into the tissue of the oyster or mollusk, then returning it to the sea, allowing a cultured pearl to develop naturally. This practice was already quite widespread culturing hemispherical pearls known as mabe pearls. Kokichi Mikimoto is credited with perfecting the technique for artificially stimulating the development of round pearls in akoya mollusks, receiving a patent for this technique in 1916. Although patented in 1916 this technique has since been improved upon and used extensively throughout the pearling world - no longer simply used to cultured akoya pearls, but freshwater, South Sea and Tahitian pearls as well.

Mikimoto opened the door to a greatly expanded pearl industry in which pearls could be farmed like an agricultural crop. These cultured pearls could now be produced in sufficient quantities to make them available to virtually anyone.

The cultured pearl industry has now far surpassed that of the natural pearl industry. Although a market still exists for pearls gifted to us by nature, these pearls are becoming more and more difficult to find, with rare full strands being auctioned for hundreds of thousands of dollars. Today, purchasing pearls from nearly any store in the world means purchasing a strand of cultured pearls.