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Luster: The “soul” of a pearl lies in its iridescence. Luster grades are categorized as extremely strong, strong, medium, weak, and non-lustrous. A simple way to identify luster is to observe the pearl’s reflective surface—pearls with extremely strong luster will clearly mirror outlines, exuding a stunning sheen. The brighter the luster, the higher the price.
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Blemishes: As the saying goes, “no pearl is completely flawless.” Pearls are formed by shellfish, so blemishes are common. Typical imperfections include growth lines, wrinkles, waistlines, pits, and spiral marks. Perfectly flawless pearls are extremely rare. The smoother and fewer blemishes on a pearl’s surface, the higher its value.
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Color: Pearls come in a wide range of colors, with rich and beautiful overtones. In addition to their base body color, pearls also exhibit secondary colors and iridescent overtones.
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Variety and Size:
Different pearl varieties vary in size due to the different shell species that produce them:
- Akoya pearls: Known for excellent luster and overtones, sized between 2–10mm (common: 6–9mm).
- South Sea white pearls (Australian white pearls): High luster, sized 8–19mm (common: 9–15mm).
- South Sea golden pearls: Smooth and delicate surface, sized 8–19mm (common: 9–15mm).
- Tahitian pearls: Predominantly black, sized 8–18mm (common: 8–13mm).
- Freshwater pearls: Diverse colors and sizes; some with high luster and flawlessness can rival seawater pearls, sized 2–18mm (common: 2–15mm).
- Shape: According to conventional market standards, rounder pearls generally command higher prices. However, with evolving aesthetics, uniquely shaped pearls are gaining popularity.
In addition to the six key factors above, nacre thickness also affects a pearl’s appearance, though it cannot be judged by the naked eye. It must be measured by a certification institution and stated in the appraisal report. Longer cultivation times result in thicker nacre, making the pearls more durable and longer-lasting. However, proper daily maintenance also influences a pearl’s lifespan.
