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. Four categories determine the types of pearls: saltwater, freshwater, natural, and cultured.

Saltwater vs. Freshwater Pearls

Three species of mollusks found in the coastal waters of the Pacific produce the majority of saltwater pearls:

• 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, 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 a 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 by mollusk type. 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 called tissue nucleation, resulting in a pearl composed of pure nacre.

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

Pearl Grading

Maui Divers Jewelry uses a 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 all determine a pearl's quality.

Pearl Sizes

All pearls are measured in millimeters — the diameter for spherical pearls, and the width for all other shapes.

Pearl Shapes

(Baroque Pearl Shapes)

Pearls come in many shapes, but most fall into one of eight categories:

• Round — Very rare; rolls smoothly across a flat surface.
• Semi-Round — Appears round to the naked eye, but wobbles 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; may be a very irregular shape.
• Circled — Contains one or multiple rings around the pearl.

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

Pearl Surface Quality

Pearls typically have minor surface imperfections, abnormalities, blemishes, or birthmarks — and these birthmarks are what make each pearl unique. Blemish type, size, number, location, and visibility all determine a pearl's surface quality. Blemishes may affect both how a pearl looks and how durable it will be. The twelve types of blemishes that naturally occur on pearls include: abrasion, bump, chip, crack, flat areas, gap, pit, ridge, ring, scratch, spot, and wrinkle.

Four classifications of surface quality help determine the severity of blemishes:

• 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 is what makes each one unique.

Pearl Colors

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

• Body color: The most prevalent color of the pearl.
• Overtone: A luminous color layered over the body color; when concentrated on the edges of the pearl, it is referred to as the "halo."
• Orient: A prismatic layer of color just below the surface of the pearl.

Not all pearls will demonstrate all three color characteristics.

Pearl Nacre

Nacre, commonly referred to as mother-of-pearl, is the iridescent inner layer of mollusk shells and the substance from which pearls are formed. This remarkable composite — made 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 curate 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 among other jewelry or in an airtight compartment. Their soft surface scratches easily — store them in a separate cloth pouch.
2. Human skin is naturally acidic, and this acid eats away at pearls over time. Gently wipe your pearls with a soft, slightly damp cloth after wearing.
3. Clean pearls occasionally with a mixture of warm water and non-detergent soap. Lay them flat to dry before storing.
4. If you wear pearls frequently, restring them as needed.
5. Remove pearls before swimming, exercising, washing dishes, gardening, applying makeup, perfume, or hairspray, or using any harsh detergent or chemical.
6. Never wear your pearls while they are still wet.

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