Interesting facts about pearls

Pearls are hard crystalline objects produced in the mantle of a living shelled mollusk.

Pearls are made of calcium carbonate just like this is the case with the shell of the mollusk.

Not all pearls have ideally round shape and smooth surface because there are many other shapes of pearls. In fact, pearls come in eight basic shapes: round, semi-round, button, drop, pear, oval, baroque, and circled.

A very large number of shelled mollusks are capable of producing pearls though most of these pearls don't have a gemological value and are not used for jewelry purposes. Term gem-quality pearls only refers to nacreous and iridescent pearls.

The largest pearl in the world is the Pearl of Lao Tzu, sometimes also referred to as The Pearl of Allah. This gigantic pearl measures 24 centimeters in diameter (9.45 inches) and weighs 6.4 kilograms (14.1 lb). It was discovered in 1934 from the Island of Palawan in the Philippines and has an estimated value of $60 million despite not being the gem-quality pearl.

The ocean acidification is a huge threat to future pearl production because ocean are becoming more acidic and since they are made of calcium carbonate they are under threat for even the small rise of acidity in oceans.

Pearls can be also divided to freshwater and saltwater pearls. China is the world's largest producer of freshwater pearls.

The creation of pearl doesn't happen overnight. This is a rather long and slow process, because the material first must be extracted from sea water and then processed by special cells in the mollusk's body. Sometimes it takes up to 20 years for the creation of precious natural gem-quality pearls.

Pearl oysters very rarely produce naturally black pearls and this is the reason for their expensive price tag. The black pearls are also called Tahitian pearls because the oyster and pearl are indigenous to the pure blue lagoons of French Polynesia. The cultured Tahitian pearl farms are located in the blue lagoons of the Tuamotu-Gambier Archipelago, which belongs to the five archipelagos that make up French Polynesia. Tahiti is the main archipelago.

The pearls produced by Pinctada maxima pearl oyster are called South Sea Pearls. Among the most valuable South Sea Pearls are the white pearls from Broome area of Australia and golden ones that come from the Philippines.