The pearls are gems grown within the soft tissue of an oyster around a microscopic irritant such as a grain of sand that found its way inside the shell. There are two types of pearls identical in composition and appearance and different only in how they were conceived – natural and cultured.
Natural pearls are seeded naturally, while cultured pearls are acquired through farming and harvesting processes where the mollusk is seeded by humans. In both cases, the mollusk coats the irritant with layers of inorganic deposits called nacre, creating a pearl. Natural pearls are scarce and expensive. The vast majority of the pearls available on the market today are cultured.
Nacre is the material of which pearls are composed; it consists of aragonite – calcium carbonate, and conchiolin, a complex protein forming mollusk shells. It is strong, resilient, and iridescent.
The highest quality Akoya pearls originating from Japan are called Hanadama Akoya, “flower pearls” in Japanese. Akoya pearls have highly desirable white, grey, cream, and blue body color with silver, pink and green overtones ranging from two to ten millimeters. They are commonly perfectly round in shape, although irregular-shaped Akoya pearls can also be found.
South Sea pearls are the most sought-after variety of pearls, often called the Queen of Pearls. The high failure rate during the cultivation process makes South Sea pearls one of the most valuable on the market. The perfectly spherical specimens without dents and blemishes are rare and command very high prices.
The Melo sea snail makes the orange-hued pearl prized for its flame-like appearance.
Conch are exceptionally rare pink pearls made of a porcelaneous (non-nacreous) material.
- Wrinkles result from uneven growth of the nacre due to odd-shaped seeds
- Spots are slight color variations
- Abrasions are scratches or scuffs that impact the luster of the pearl.
- Dents, divots, and pits are various indentations in the nacre.
- Mottling and bulleting is a pattern on the surface created inside the oyster. It can be desirable because it indicates a thick layer of nacre.
- Kobs and tips are growth marks.
- Circles are a growth pattern that imparts a unique look and is not considered a blemish.
Saltwater pearls come in three main varieties. They generally have a better quality than freshwater pearls, reflected in their higher demand and price. The most common varieties include Akoya, South Sea, and Tahitian pearls. Before the Japanese started cultivating Akoya in the early 20th century, pearls were rare and expensive. Today Akoya is the most abundant variety of saltwater pearls.
With their perfectly spherical shape and high luster, Akoya pearls are formed by small Pinctada fucata oysters, also known as Akoya oysters. They come from waters surrounding Japan, China, Korea, and Vietnam. Each oyster can produce only one or two pearls at a time, and the limited production increases their value.
South Sea pearls are the most sought-after variety of pearl types cultivated in Australia, the Philippines, Myanmar, and Indonesia. They grow inside the Pinctada maxima oysters, which are the largest pearl oysters in the world. The South Sea pearl color palette consists of white and golden hues, with pink, green, and blue overtones. South Sea pearls can grow up to 22 millimeters in diameter and are highly prized for their satin-like luster, elegant appearance, and size.
Tahitian pearls come exclusively from Tahiti and other French Polynesian islands and are the most sought-after naturally dark gems. They are produced by the black-lipped Pinctada margaritifera oyster, which doesn’t live anywhere else. Tahitian pearls occur in black, dark grey, charcoal, peacock green, and aubergine colors with silver, lavender, and blue overtones. They can grow as large as 21 millimeters. However, less than 10% of the harvest qualify for export because, according to the internationally accepted quality standards, a true Tahitian pearl should have a nacre at least 0.8-millimeter thick. Tahitian pearls were once coveted by Queen Elizabeth I.