Pearl Farming
Growing pearls deliberately: nucleating molluscs, tending them in water for months or years, then harvesting.
After nucleation the molluscs are suspended in nets and cleaned regularly, since fouling slows growth and can kill them.
Freshwater pearls need two to six years, Akoya about ten to eighteen months after nucleation, and South Sea two to four years.
Water temperature, plankton and storms all affect a crop, so pearl farming is agriculture with the same exposure to a bad season.
When you are buying
The time in water is the single biggest driver of nacre thickness, and therefore of how long a pearl lasts. It is a fair question to ask about any saltwater pearl.
Nucleation
The operation that starts a cultured pearl: inserting a bead, a piece of mantle tissue, or both.
Pinctada
The genus of marine oysters that produces every commercially important saltwater pearl.
Nacre
The material a pearl is made of: microscopic aragonite platelets glued in layers by conchiolin. Thickness determines both lustre and lifespan.
Freshwater Pearl
A pearl grown inside a mussel in a river or lake, rather than an oyster in the sea. Most pearl jewellery sold today is freshwater.
South Sea Pearl
The largest commercially grown pearl, from the gold-lipped or silver-lipped oyster. Typically 9mm to 16mm, white to deep gold.