Nacre Acceptable — GIA Cultured Pearl Nacre Grade
Nacre Acceptable — GIA Cultured Pearl Nacre Grade
The standard grade indicating sufficient nacre coating for durable wear and good appearance
Acceptable is a grade on the GIA cultured-pearl nacre-thickness scale indicating that a beaded cultured pearl has sufficient nacre coating to support durable wear and good visual appearance. The grade is the standard target for commercial-quality bead-cultured pearls and represents adequate nacre deposition over the cultivation period.
Definition
GIA's two-grade nacre scale for beaded cultured pearls runs Acceptable and Nucleus Visible. Acceptable indicates that the nacre coating is even, does not show the bead nucleus through the surface as a chalky patch, and supports the typical lustre and orient expected of the pearl variety. Nucleus Visible (NV) indicates that the nacre is too thin to fully cover the bead and shows visible chalky areas that compromise both appearance and durability.
Thickness in practice
For Akoya saltwater bead-cultured pearls, nacre at the lower end of Acceptable typically measures around 0.3 to 0.4 millimetres; better-quality production runs 0.4 millimetres and above, with longer cultivation periods producing thicker coatings. South Sea and Tahitian pearls develop substantially thicker nacre over multi-year cultivation periods, often 1 to 5 millimetres, and routinely fall well within the Acceptable grade.
Trade significance
Pearls graded Acceptable are suitable for everyday wear in standard mounted jewellery — strands, earrings, pendants, rings — and represent the bulk of the international cultured-pearl supply. The grade does not by itself signal high value; pricing is driven primarily by size, lustre, surface quality, colour, and shape. Within the Acceptable range, pearls with thicker nacre command premiums over those at the lower end because of better durability and stronger lustre.