How cultured pearls are made
The bead inside a Tahitian pearl is cut from freshwater mussel shell, and the best shells come from the Mississippi.
- stations
- 6
- things upstream
- 2
- raw sources
- 2
- step from the ground
- 1
The short version
Pearl farmers raise oysters for years, then open each one and insert a polished shell bead beside a scrap of mantle tissue from a donor. The tissue grows into a sac around the bead and coats it in layer after layer of nacre. Two years later, the pearls are harvested, sorted, drilled and strung.
-
Raise the young oysters
Larvae settle on plastic lines in a lagoon and move to underwater stations, where they are scraped clean of hitchhikers several times a year. After about three years they are big enough to graft.
10-12 centimeters across
Goes in -
Carve the seed beads
Beads are cut and polished into spheres from freshwater mussel shell. Each bead will become the center of a pearl.
-
Graft the oyster
A technician opens the oyster and sets a polished bead and a small piece of donor mantle tissue side by side in its gonad. The tissue's outer cells multiply and spread over the bead to form a pearl sac.
-
Hang them in the water
Back in the sea, the oysters sit in nets or cages while the sac lays down thin coats of nacre, the same material that lines the inside of the shell.
Goes in -
Open and harvest
After about two years, workers open the oyster and take out the pearl. A healthy oyster may receive a new bead the same size as the pearl it just gave up, with no new tissue needed.
-
Sort and string
Pearls are washed, polished and sorted by size, shape, color and luster, then drilled and strung into necklaces.
Worth repeating
- More than 99% of all pearls sold worldwide are cultured pearls.
- A Tahitian pearl harvest comes about 5 years after the oyster first settles as a larva.
- An oyster that has given up a good pearl can be regrafted at once, with a bead as big as that pearl and no new tissue.
Back to the ground
Follow every input upstream and cultured pearl starts as these 2 raw sources.
Open the whole family tree
Keep walking
Sources
Cite this page: "How cultured pearls are made." Assembly Line, 2026-11-03. https://assemblyline.org/make/cultured-pearl