Depending on the type of oyster that produced them and what part of the world they are from, pearls come in a wide range of shapes, lusters, and mysterious colors. The following introdution is mainly about akoya pearl and freshwater pearl.
Akoya Pearl
Akoya Pearls are produced by the Japanese Akoya Oyster. Best known for their deep luster, rich color, and perfect round shapes, Akoyas are the most popular and classic.
The Akoya cultured pearl made its debut in 1905 when Kokichi Mikimoto first introduced the technique to produce round pearls by the process of bead nucleation. Already by 1920, he had accomplished his lifelong dream to adorn the necks of ladies all around the world with his revolutionary Akoya cultured pearls.
Akoya Pearls over 9mm are rare and highly valued on the market. Given that the Akoya oyster is the smallest commercial pearl jewelry producing oyster, the pearls tend to be small and are usually limited to producing no more than 2 pearls per harvest. Compare that to the freshwater pearl producing mussel that is capable of producing over 40 pearls at a time, and it is no surprise that Akoya Pearls command a higher value than freshwater pearls of similar quality.
Akoya Pearls range in body color and overtone. Body color, referring to the basic color of the pearl, includes white, cream, green, silver, pink, and gold. Akoya overtones, or tints as seen in the central areas of the pearl under light, include rose (pink), green, silver, and blue. The most rare and valuable Akoya Pearl color is white with rose overtones; a green overtone is considered less desirable in white colored pearls and its presence reduces value.
Freshwater Pearl
Freshwater pearls are the most common type of pearl and produced primarily in China by the freshwater pearl mussel Hyriopsis Cumingi. These pearls are best known for their unusual shapes, wide variety of sizes, and range in colors.
Differing from that of saltwater pearls, the process used to produce freshwater pearls does not require a shell nucleus but rather a tissue grafting technique that facilitates mass production. The mussel is also larger than that used to produce Akoya Pearls, resulting in the simultaneous production of up to 50 pearls at a time. Because only a mantle tissue is used without a bead nucleus, top quality freshwater pearls are essentially all nacre and offer a very good value.
Freshwater pearls are available in a rainbow of natural colors and shapes, a much wider variety than saltwater pearls, giving them a special allure. Colors include white, orange, lavender, purple, violet, blue, rose, and silver. The variety of shapes includes round, drop, coin, button, rice, stick, and potato. Freshwater pearls vary in size from 2mm to 15mm.
