Bodycolour is the dominant overall hue of a pearl, evaluated independently of overtone (a secondary translucent colour layered above the bodycolour) and orient (the iridescent surface play that some pearls show). Bodycolour is the first component the trade and laboratory graders read when describing pearl colour, and it is the principal colour designation that appears on a strand description or a laboratory report. The full colour description of a pearl is composite; bodycolour is its base, with overtone and orient evaluated against it.

Range across pearl types

Akoya pearls show white, cream, and silver bodycolours, with the trade preference and price premium attaching to clean white. The cream and yellow tones occasionally seen in unbleached Akoya are removed by the standard bleaching protocol, leaving the commercial product near pure white. South Sea pearls show pure white through silver to deep golden, with both ends of the range commercially significant — Australian white South Sea and Indonesian and Philippine golden South Sea command separate markets and separate price structures. The intermediate cream and champagne South Sea tones are also marketable, particularly in the Asian markets that prefer warmer-toned pearls.

Tahitian pearls show grey through black bodycolours, with peacock, aubergine, and pistachio commonly described not as bodycolours but as overtone modifications visible on a grey or dark base. The most desirable Tahitian bodycolour is a clean dark grey with strong peacock or aubergine overtone; the least desirable is a flat dull black with no overtone play. Freshwater pearls show white, peach, lavender, and pink bodycolours, with a wider natural-colour range than the saltwater types and with bodycolour driven principally by the donor mussel species and the freshwater chemistry of the cultivation pond.

Determinants

Bodycolour is determined principally by the species of mollusc, the colour of the donor mantle tissue used in nucleation, and water-chemistry conditions during the cultivation period. Trace elements absorbed into the conchiolin matrix during nacre deposition contribute to the colour, and the proportion of conchiolin to aragonite affects how light interacts with the nacre. The mantle tissue's colour is reproduced in the pearl sac and is therefore the strongest single determinant of bodycolour for bead-nucleated pearls. The interaction is biological rather than mineralogical, which is why pearl bodycolours run in continuous gradations rather than the discrete categories typical of mineral gemstones.

Treatment can alter bodycolour. Bleaching lightens cream and yellow tones toward white. Dyeing introduces colour, most commonly silver-nitrate dyeing of freshwater or Akoya pearls toward grey or black to imitate Tahitian product. Irradiation darkens the bead nucleus and shifts apparent bodycolour toward grey or blue. All three treatments must be disclosed under CIBJO and AGTA codes, and laboratory reports flag treated bodycolour where detected.

In the trade

Bodycolour grading is the first step in colour assessment; overtone and orient are evaluated against the bodycolour as base. A laboratory report describes pearl colour in the format bodycolour-overtone, e.g. white with rose overtone or grey with peacock overtone. The bodycolour drives type classification — a black pearl is a black-bodycolour pearl — and contributes most of the price differentiation between pearl-colour categories. Within a colour category, overtone and orient drive the further differentiation between standard and premium examples.

Further reading

• GIA — Pearl quality factors and colour grading
• AGTA — pearl colour reference
• International Gem Society — pearl colour