Growing South Sea pearls with no enhancement means farming the oyster as close to its natural life as possible. Australian pearl farmers have spent more than 50 years learning how Pinctada maxima builds nacre of this quality, and the method still comes down to clean water, patience and careful handling.

Step 1: Diving

It starts in the clear waters off north-western Australia, around Broome and the Eighty Mile Beach, with the collection of wild Pinctada maxima oyster. Working from ocean-going vessels, divers hand-pick oysters off the seabed. Hand collection is a responsible form of commercial fishing: it does no damage to the seabed and produces no wasteful by-catch, unlike dredging.

Step 2: Seeding

Implanting the nucleus each pearl grows around is meticulous, specialised work. On board the pearling ships the oysters sit in tanks of constantly circulating seawater until a technician delicately inserts a polished sphere cut from Mississippi freshwater mussel shell. That material costs more, but it is used because its chemical composition and density are almost identical to a natural pearl, which helps the oyster accept it. Once seeded, the oysters go back to the sea.

Step 3: Husbandry

Keeping the oysters healthy is what produces a good pearl. Over the two to three year growing period each oyster is individually cleaned every ten to fourteen days to scrub off the marine growth (algae, barnacles, sponge) that would otherwise smother it and stunt nacre deposition.

Step 4: Harvest

After a minimum of two years the oysters are lifted from the sea and brought to the mother ships. Nobody knows the result until the technician eases the pearl out. The work is done gently because a healthy oyster can be re-seeded for a second and sometimes a third pearl, which is also why the largest South Sea pearls come from older, repeatedly seeded oysters.

Step 5: Grading

Each pearl is sorted individually on the "Five Virtues": luster, complexion (surface), shape, color and size. The pearls are graded exactly as they leave the oyster with no polishing or treatment. Paspaley, the main producer of Australian South Sea pearls, sorts into close to 6,000 categories. It is exacting work, and it is the only way to keep a strand consistent in color and size. Note that AAA/AA/A you see at retail is a trade grading scale, not a GIA standard.

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