Pearl - the birthstone for June, is amongst the most timeless, classic and treasured of all gems. Throughout history, these noble gems have been associated with wisdom, wealth, purity, romance and mystery. It's hard to believe that such a luscious, beautiful gem comes from such humble origins. Here, you will learn more about the pearl you own or are likely to be a proud possessor of.

Pearl Types

Thanks to the culturing of pearls, there is a wide range of pearls available to us, at not too high a cost. These various pearl types are dependent upon the type of mollusk that forms them, as well as the environment in which they develop, and their location. Different pearl types vary in pearl luster, pearl color, and even pearl sizes. However, each one has its own beauty, its own style, and its own wonder.

The following are the types of pearl that you're most likely to see in today's pearl marketplace.

South Sea Pearls are among the largest commercially harvested cultured pearls in the world. The average size of a South Sea pearl is 13 mm, with most harvests producing a range of sizes from 9 mm to 20 mm. The South Seas lie between the northern coast of Australia and the southern coast of China. These waters are the native habitat of a large oyster known as Pinctada maxima from which this variety of pearls is derived.

South Sea pearls are also the most expensive pearl on the market, due to their rarity and thick nacre. Two reasons account for this: the rarity of a pearl of such size and high luster, and the difficulty of gathering acceptable quantities from these oysters due to their extreme sensitivity to the culturing process. It is the most rare and extraordinary pearl you will find in jewelry.

South Sea pearls also have a subtle array of colors; typically white, silver, and golden, that is rare in other pearl types.

 

Akoya Cultured Pearls are the classic white pearl and typically have the highest luster and greatest shine of all cultured pearls. They are cultured in pearls from saltwater mollusks from Japan and China and are popular for their luster and beauty.

The Akoya oyster is the smallest pearl-producing oyster used in pearl culture today, so Akoya pearls also tend to be small. Typical Akoya pearls range from 5 mm to 11 mm, with the 10 and 11 mm sizes being rare. The Akoya pearl color ranges from cream, white, rose and gold to blue-gray in body color and typically have a rose, cream or Ivory overtone. Akoya pearls may also be treated to achieve a black body color.

 

Freshwater Cultured Pearls come from freshwater mussels and are dated as far back as the thirteenth century, primarily produced by China. Made in a freshwater mollusk in a lake, pond or river, they are similar in look to the Akoya pearls, but are less expensive because they are generally smaller and less symmetrical.
A freshwater pearl comes in a variety of shapes, ranging from round to off-round, rice-shaped to baroque. The typical size of freshwater pearls is 2mm - 16mm with 7mm - 8mm being the most common. A round freshwater pearl appears very similar to an Akoya pearl, but is almost one-fifth the price. So it is the perfect gift when shopping on a budget. Also, because freshwater pearls are solid nacre, they are also quite durable, resisting chipping, wear, and degeneration.

Freshwater pearls come in various pastel shades of white, black, pink, peach, lavender, plum, purple, and tangerine, depending on the type of mussel.

 

Tahitian Cultured Pearls are produced in the black-lipped oyster Pinctada margaritifera , in and around Tahiti and the French Polynesian islands. This oyster itself is quite large which often results in much larger-than-average pearls, typically 9mm - 16mm. They are slightly smaller than the South Sea pearl, on average, but larger than the Akoya. These pearls are unique because of their natural dark colors. They are very unique and expensive because of the complicated cultivation process.

Though traditionally called "black", these pearls range in color from metallic silver to the color of pencil graphite with gray, silver, green, blue or purple overtones.

 

Mabe Pearls is a hemispherical shaped pearl which is grown against the inside of the oyster's shell, rather than within its tissue. Mabes occasionally appear in nature. Cultured Mabes are used for such things as rings and earrings, rather than for stringing on necklaces. They tend to be very beautiful with high luster and orient, but are priced much lower than round pearls.

Pearl Quality

Pearls are unique among gemstones. Pearls are the natural, organic products of living creatures, and they have different grading standards. The most commonly used and internationally recognized ranking system consists of B, A, A+, AA, AA+, and AAA to grade the pearls. On this scale, AAA is gem-quality, and the absolute highest quality pearl available.

Six accepted factors determine the quality, value, and beauty of pearls. They are nacre, luster, surface, shape, color and size. These six factors are universally accepted as the main factors in grading a pearl.

• Pearl Nacre: Nacre is the natural substance that a mollusk like a mussel or oyster secretes to protect its sensitive flesh from irritants such as sand, shell fragments or implanted beads. This nacre is the same iridescent material that lines the inner surface of the oyster shells, aptly named mother-of-pearl. As a general rule, the thicker the nacre, the higher quality the pearl is.
• Pearl Luster: Luster is quality of a pearl that shows its mirror-like reflecting ability and surface brilliance - its glow. The luster of good quality pearls should be bright. Found on the very surface, luster is measured by the sharpness and brilliance of the reflection. A good quality pearl captures light well and reflects it back to the observer's in an impactful manner. You'll be able to see your reflection clearly on the surface of a good pearl. Pearls appearing too white, dull or chalky are not of high quality.

Grades of Pearl Luster are:

• Very High -> AAA
• High -> AA & AA+
• Medium -> A & A+
• Soft -> B

When reflections are bright and sharp, pearls are said to have high, or very high, luster. When the light reflections are weak or fuzzy, pearls are described as soft or dull. High luster pearls are obviously coveted as the luster plays a significant role in the beauty of a pearl. High luster can make up for sub-par size, shape, color and surface.

• Pearl Surface: A pearl's surface is probably the most obvious and easiest to observe. The cleaner the surface of the pearl, the more valuable it is. Look for an absence of disfiguring spots, bumps, cracks, discolored portions, areas of low or uneven nacre appearance, or any other flaw on the surface of a pearl, also known as "cleanliness." Notice that the highest quality pearls have a sharp, mirror-like reflection. The ideal good quality pearl is one that is free of imperfections.

The surface quality of a cultured pearl is rated as follows:

• Clean-Very Lightly Blemished -> A quality
• Lightly Blemished -> B quality
• Moderately Blemished -> C quality
• Heavily Blemished -> D quality

All surface grading is done with the naked eye (no magnification device like a jeweler's loop) and is very subjective, depending greatly on the expertise of the grader.

• Pearl Shape: Pearls develop in all shapes, especially freshwater and Tahitian pearls. They can be round, semi-round, drop, oval, half-rounded, semi-baroque and baroque shapes. The general rule of thumb is, the rounder a pearl is, the better the quality, assuming all other factors are the same. A perfectly round pearl is very rare. Other shapes that are not symmetrical in shape, can be lustrous and appealing, and typically cost less than round pearls.

To be considered round, a pearl must be a perfect sphere whose diameter variation rate is less than 2%. A near-round pearl is a slightly imperfect sphere whose diameter variation rate is greater than a round's 2%, but less than 5%. A semi-baroque pearl exhibits at least one axis of rotation (it can be spun on a table top) and is subdivided into four shapes: drop, button, pear and oval. A baroque pearl does not have any axis of rotation at all (cannot be spun on a table top).

• Pearl Color: Pearls come in a variety of colors, from white to black and every shade in between. The color of a pearl is a combination of two components - its predominant basic body color and its overtone, and it is important to distinguish between the two. The body color of a white pearl may appear in white, pink, cream, champagne, aqua, golden, green or black. An overtone is the color that overlies the body color resulting from the layers of the nacre, and may be seen under different angles of the light.

Typical overtones are rose, pink or silver. Every pearl developed appears with a different color combination, which makes it truly unique from other pearls. Color itself is not the basis in grading pearls rather it is color intensity. A good quality pearl possesses a deep and equal overtone while a bad one possesses the opposite.

• Pearl Size: Measuring the size basically means measuring the diameter of the pearl expressed in millimeters. Tiny seed pearls can be smaller than 1 mm, while South Sea pearls as large as 20 mm have been found. If all other quality factors are equal, the value of the pearl rises gradually with size. Round and off round pearls are measured by the shortest diameter. All pearls in other shapes are measured along two diameters (the longest and second longest).

It is important to remember that size alone however is not enough to tell the quality of the pearl.