South Sea pearls are renowned for their large sizes. The Pinctada maxima oyster is the largest species of oyster capable of producing a pearl. South Sea pearls are measured in millimetres and commonly range from 9-20+mm, with the majority falling within a range of 10-17mm. Though extremely rare, the irregularly shaped baroque South Sea pearl can reach sizes of up to 40mm or more. The largest fine quality, round South Sea pearl cultivated by one of our producers measured in at a magnificent 22.8mm.

Pearls are generally measured using a milligauge which can measure the pearl to within 0.01mm accuracy. The exception is in relation to the size of baroque pearls which is usually impossible to measure by milligauge because of their irregularity. Consequently, baroque pearls are measured by sieve.