Cultured Pearl
| Category |
| Organic |
| Crystal Form |
| Orthorhombic |
| Moh's Scale Hardness |
| 2.50–4.50 |
| Specific Gravity |
| 2.72–2.78 |
| Refractive Index |
| 1.53–1.68 |
| Sources |
Akoya Pearl South Sea Pearl Tahitian Pearl |
Cultured pearls have make up 90% of the total pearl market. Not every natural pearl are formed in such a way that is valuable and attractive. In the 20th century, pearl inhabitant were considerably decreased.
Cultured pearls exist as early as the 13th century in China by placing a small object to the inner wall of the shell and covered by nacre. In 1761, first round cultured pearl were produced in Sweden, by Carl von Linné. The modern cultivate techniques are discovered by experiments, Kokichi Mikimoto is one of the well-known innovators of this technique. In late 1800s, the nucleus is made out of a rounded mother-of-pearl bead (from the shell of mollusk) and wrapped with a piece of tissue (from the mollusk’s mantle). The bead and the piece of tissue are then inserted into the oyster as nucleus of pearl and continue to grow inside the oyster.
How are cultured pearls made?
Cultured pearls usually have a nucleus. The insertion of the bead into the mollusk requires a lot of skills. The nucleus usually made up of a rounded mother-of-pearl bead (from the mollusk’s shell), wrapped with a piece of tissue (from the mantle of a mollusk). A shell has to be carefully opened, and then the nucleus is inserted into the mollusk. Over time the object will be coated with layers of nacre. Not all oysters will accept the insertion; some oyster will become ill after the operation and some will not survive. For oysters that have accepted the nucleus insert will continue onto the next stage of cultivation.