A Guide to Tahitian, Freshwater, South Sea, and Akoya Pearls

Pearls are beautiful and mysterious, each one with its own distinct characteristics.

Pearls are one of nature's most distinctive and colorful gems. They come from oceans, rivers, lakes, and ponds, and each one is unique. We’ll help you learn about different types of pearls—including South Sea, Tahitian, Freshwater, and Akoya—and how they are graded.

All pearls are formed inside mollusks or oysters, and four categories determine the types of pearls: saltwater, freshwater, natural, and cultured.

Saltwater vs. Freshwater Pearls

Three species of mollusks, which are found in coastal waters of the Pacific, produce the majority of saltwater pearls. These include:

• Akoya oyster (Japan, China, Australia, and New Guinea)
• Black-lipped oyster (Tahiti/French Polynesia, and South Pacific)
• Silver-lipped or Gold-lipped oyster (South Pacific, Australia, Philippines)

The most common freshwater pearl-producing mollusks, which are found in the freshwater bodies of Asia and North America, include:

• Wrinkle Shell or River Shell (China, Vietnam, Japan, and Korea)
• Triangle Shell (China)
• Washboard (North America)

Natural vs. Cultured Pearls

A pearl forms naturally when a foreign object, like a grain of sand or parasite, enters a mollusk's shell. To protect itself, the mollusk coats the object with layers of a substance called nacre (the same material as its shell lining). For cultured pearls, humans intentionally insert a similar object to start the process.

The cultivation process varies depending on the type of mollusk. In saltwater mollusks, a round bead and a piece of mantle tissue are inserted to initiate pearl growth, a technique known as bead nucleation. For freshwater mollusks, only a piece of mantle tissue is used, a process known as tissue nucleation, resulting in a pearl with pure nacre.

Pearl of Wisdom: Various mollusks can produce pearls, but most pearls come from a few select species.

Pearl Grading             

Maui Divers Jewelry uses its proprietary grading system, adapted from the GIA (Gemological Institute of America) standard, to ensure proper pearl grading.

Size, shape, surface quality, color, nacre, and matching determine a pearl's quality.

Pearl Sizes

• Millimeters measure the size of all pearls—the diameter of spherical pearls and the width of all other shapes.

Pearl Shapes

(Baroque Pearl Shapes)

Pearls come in many different shapes, but most will fall into one of seven categories:

• • Round
    • Very rare and rolls smoothly across a flat surface
  • Semi-Round
    • Appears round to the naked eye, but will wobble when rolled on a flat surface
  • Button
    • Symmetrical with a flattened shape
  • Drop
    • Symmetrical teardrop shape
  • Pear
    • Symmetrical pear shape
  • Oval
    • Elongated, forming an oval or egg shape
  • Baroque
    •  No symmetry, and may be a very odd shape.
  • Circled
    • Contains singular or multiple rings around a pearl 

(Example of Baroque, Circle, Semi-Round, Drop, and Button Pearls)

Pearl Surface Quality

Pearls typically have minor surface imperfections, abnormalities, blemishes, or birthmarks. These birthmarks are what make each pearl unique. Blemish type, size, number, location, and visibility determine the surface quality of a pearl. Blemishes may not only affect how a pearl appears, but may also affect how durable it will be. The twelve types of blemishes that naturally occur on pearls include an abrasion, bump, chip, crack, flat areas, gap, pit, ridge, ring, scratch, spot, or wrinkle.

Four classifications of surface quality help determine the severity of the blemishes on a pearl:

• • Heavily blemished (severe natural birthmarks)
  • Moderately blemished
  • Lightly blemished
  • Clean (perfect or nearly perfect)
    

Pearl of wisdom: All pearls have some kind of "birthmark" which makes the pearl unique.

Pearl Colors

Pearls are available in a wide array of colors. The most common include white, cream, silver, gold, gray, black, and brown. The color encompasses three characteristics:

• • Body color: The most prevalent color of the pearl
  • Overtone: The luminous color in a layer over the body color, and when concentrated on the edges of the pearl, is referred to as the "halo."
  • Orient: Just below the surface of the pearl is this prismatic layer of coloring.

Not all pearls will demonstrate all three color characteristics.

Pearl Nacre

Nacre, commonly referred to as mother-of-pearl, is the enchanting, iridescent inner layer of mollusk shells and the exquisite substance from which pearls are formed. This remarkable composite, composed of calcium carbonate and conchiolin, is celebrated for its exceptional strength, resilience, and captivating beauty.

Pearl Matching

Matching reflects the harmony and elegance required for pearl jewelry, especially in strands and earrings. Consistency and uniformity ensure each pearl complements the others, creating a cohesive and stunning effect. The Pearl Experts at Maui Divers Jewelry carefully create the ideal match for all pearl keepsakes.

How to Care for Your Pearls

Pearls are delicate and require special care. These six tips will help your pearls stay beautiful for years to come:

1. Do not store pearls amongst other jewelry or in an airtight compartment. Their soft surface can be scratched easily. Store them in a separate cloth pouch.
2. Human skin is naturally acidic, and this acid eats away at pearls over time. To remove the acid, gently wipe your pearls with a soft, slightly damp cloth.
3. Clean pearls occasionally with a mixture of warm water and non-detergent soap. Lay them flat to dry before you put them away.
4. If you wear pearls frequently, restring your pearls as needed.
5. Pearls should be removed when swimming, exercising, washing dishes, gardening, applying makeup, perfume, hairspray, or using any type of harsh detergent or chemical.
6. Never wear your pearls while they are still wet.