Five S’s classification


Of all the pearls across the globe, there is one that is rare and revered. In pristine waters where the temperature is gentle and the atmosphere nurturing, there is a pearl with a strange perfection which bears the fingerprint of forever, the South Sea pearl.

The South Sea pearl is a labour of love, spending two silent years within the host oyster – the Pinctada maxima (commonly known as the silver or gold lip) or the Pinctada margaritifera (commonly known as the black lip). The breathtaking gift that is finally delivered into our world is well worth the wait.

AUTORE’s critically acclaimed pearl classification guide, the AUTORE Five S’s™ was launched in 2007 and continues to play an important role as an educational tool to build confidence for consumers and retailers to buy, sell and wear South Sea pearls.

Rosario Autore developed the South Sea Cultured Pearl Classification Guide which has been recognised by the respected Gubelin Gem Laboratories. The guide considers the quality of a South Sea Pearl based on its Shine, Surface, Shade, Shape and Size, and provides an in-depth explanation to understand pearl classification.

The AUTORE Five S’s is a registered trademark of Autore Pearls Pty. Ltd.

To download the AUTORE Five S®’s please click here


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.

The weighing unit for pearls is momme, an old Japanese measure of weight still used for all pearls. One momme is equal to 3.75 grams or 18.75 cts

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