Pearl

Pearl is the outlier of the gemstone world — organic, not mineral. It’s made of nacre (mother-of-pearl), the iridescent material an oyster or mussel secretes around an irritant. Most modern pearls are cultured: a technician inserts a nucleus into the mollusk and the animal does the rest over months to years.

Pearl is the softest material the trade considers a gemstone. It’s also the most lifestyle-sensitive: perfume, hair spray, sweat, and the acid in skin oils all degrade nacre over time. Care for pearls and they last a century; neglect them and they’re dull in a decade.

The four pearl types

Grading

Pearls aren’t graded on a single scale the way diamonds are. Reputable sellers describe pearls by:

• Luster — how sharp and mirror-like the surface reflection is. The single most important factor.
• Surface — the cleanliness of the surface. Tiny dimples and texture are normal; large blemishes detract.
• Shape — round commands the premium; near-round, drop, baroque, and button shapes step down in price.
• Color — body color plus overtones. Tahitian peacock overtones, Akoya rosé overtones, and South Sea gold are particularly prized.
• Size — bigger pearls command more, especially in saltwater types where size is a function of how long the oyster cultured the pearl.
• Match — for strands, how well the pearls match each other in luster, color, and shape.

Care

The single rule: last on, first off.

That means: put your pearls on after lotion, perfume, hair spray, and makeup. Take them off before showering, swimming, and exercising. The nacre is dissolved by acid (including sweat) and dulled by alcohol-based cosmetics.

Other essentials:

• Wipe each pearl with a soft damp cloth after wearing.
• Store flat in a soft cloth bag, never in a jewelry box on top of hard stones that would scratch them.
• Restring a pearl strand every 1–3 years if worn regularly — the silk thread stretches and weakens.
• Never use ultrasonic or steam cleaners on pearls. Never.

Buying

For a strand: ask about luster (the seller should have one descriptor; "AAA" alone is meaningless without context), match across the strand, and the length (16" choker, 18" princess, 24" matinee are the standards).

For an earring or pendant: pick the body color that matches the recipient’s skin tone. Cool-toned skin pairs with white or grey; warm-toned skin glows next to golden South Sea or peach freshwater.