By The Eye desk · Last verified 29 September 2026
Almost all pearls sold today are cultured, and they fall into four main types. Freshwater pearls, grown in mussels mostly in China, are the most affordable and come in many colours. Akoya pearls, usually 6 to 9mm, are the classic bright white strand. Tahitian pearls are the naturally dark ones, and South Sea pearls, often 9mm and up, are the largest and generally the most valuable. Within any type, value comes down to seven factors the Gemological Institute of America (GIA) uses: size, shape, colour, lustre, surface, nacre and matching.
Quick facts
- Freshwater: most affordable, many colours.
- Akoya: typically 6 to 9mm, known for sharp, mirror-like lustre.
- Tahitian: naturally dark, with green, blue or aubergine overtones.
- South Sea: the largest, often 9 to 20mm, in white or gold.
- Lustre is usually the biggest single factor in value.
- “AAA” grades are sellers’ labels, not GIA grades.
How do the four types compare?
| Type | Grown in | Typical size | Known for |
|---|---|---|---|
| Freshwater | Mussels, mainly in China | Wide range | Affordability and colour variety |
| Akoya | Saltwater oysters, cooler waters | 6 to 9mm | Bright lustre, round matched strands |
| Tahitian | Black-lipped oysters, French Polynesia | About 8 to 16mm | Dark colours with overtones |
| South Sea | Large oysters, Australia and South-East Asia | About 9 to 20mm | Size, thick nacre, white and gold colours |
What decides a pearl’s value?
- Lustre: how sharply the pearl reflects light. Dull lustre can cut the value sharply.
- Size: bigger is rarer; each extra millimetre adds significantly.
- Shape: round and symmetrical drops are most prized.
- Colour: body colour, overtone and orient.
- Surface: how clean it is of spots and blemishes.
- Nacre: thin nacre can wear through over time.
- Matching: how well the pearls in a strand or pair go together.
The WahLiao Verdict
Judge the lustre first: hold the pearls under a light and look for sharp reflections, not a chalky glow. A lustrous freshwater strand beats a dull Akoya one. Ignore “AAA” on the tag and ask about nacre thickness, since thin nacre is what wears out.
Questions people ask
Are cultured pearls real?
Yes. They grow inside a mollusc; people start the process. Natural pearls, which form without help, are rare and far more expensive.
What does “AAA” mean?
It’s a grade used by sellers, and it varies between them. GIA doesn’t use it.
How should I care for pearls?
Put them on after perfume and make-up, wipe them after wearing, and store them apart from harder jewellery.
Are black pearls dyed?
Tahitian pearls are naturally dark; cheaper “black” freshwater pearls are often dyed. Ask.
Sources: GIA, differences between pearl types and pearl buyer’s guide; Skyjems, the GIA 7 Pearl Value Factors; The South Sea Pearl on relative value by type.
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