Pearls · Quality

The 7 pearl value factors

GIA describes every pearl by seven factors: size, shape, colour, luster, surface, nacre and matching. Change each one on the pearl below and watch the report-style description build up. GIA classifies pearls; it does not grade them into a single score, and this page puts no price on any of them.

One pearl, seven factors

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Described like a GIA pearl report

Wording follows the GIA 7 Pearl Value Factors; this is a teaching summary, not a GIA report.

Matching: how alike the pearls are

Matching applies when pearls are worn together, in strands, earrings or bracelets. GIA's Matching Scale runs from Excellent to Poor, or Not Applicable for single pearls, and describes how closely the pearls resemble one another in size, shape, colour, luster and surface.

The four main cultured pearl types

Typical ranges from GIA's FAQ on cultured pearl types. GIA's Meet the Mollusks gives akoya 2–11 mm (average 6–8), South Sea 8–20 mm (average 13) and Tahitian 9–14 mm (most often 9–11). Freshwater pearls come in a wide range of sizes, so no single range is drawn.

Sources

  1. GIA, Pearl Quality Factors (gia.edu): the seven factors, size and shape statements, bodycolor / overtone / orient, the five luster levels with their wording, nacre and matching.
  2. GIA 4Cs, Pearl Quality 101: How GIA Examines and Classifies Pearls: seven shapes in three categories, size in millimetres, Surface Scale (Clean, Lightly Spotted, Moderately Spotted, Heavily Spotted), Matching Scale.
  3. GIA press release, GIA Introduces Expanded Nacre Scale to All Pearl Classification Reports (19 May 2025): Excellent, Very Good, Good, Fair, Poor replacing Acceptable / Unacceptable; most pearls now Good. Gems & Gemology, Summer 2025, An Update on Nacre Classification.
  4. GIA FAQ, What are the main types of cultured pearls? and GIA 4Cs, Meet the Mollusks: sizes, colours, shapes, mollusks and origins.
  5. Gems & Gemology, Summer 2021, Pearl Classification: The GIA 7 Pearl Value Factors: example report wording.