Pearl

pearl is hard, around object which by certain , mainly oysters is made, and that it is fished out for as jewel to serve. He is formed within of certain bivalvular molluscs, as a response to a bit or a another irritating particle that the shell penetrates. The mollusc puts then laagje (CaCO₃) on the particle finished, in the form of the minerals aragoniet or of lift in the transparent layers finished. As the laagjes are more thinly and more, brilliance is more fine.

Almost all pearls are nowadays grown. For this in the oyster small korreltje parelmoer are laid and the pearl can be harvested then after two years. The cultivation is by the Japanese Kokichi Mikimoto developed and patented in 1896.

The sierwaarde of a pearl depend on brilliance, colour, size, perfection and symmetry, where brilliance is most important. For this reason a small Japanese pearl is more worth than a large pearl from Quiet south sea. Perfect pearls are rare and in rings are processed. Traanvormige pearls are frequently used as a hanger and irregularly formed in collars.

Black pearl

Dorgaans are the pearl light of colour, but there are there also with a dark colour, the so-called black pearls. These become by zwartkleppige the pearl oyster Pinctada margaritifera, that in Quiet south sea lives, formed by the amputation of grey to black parelmoerstof.

Since 1963 these oysters have been grown. Young oyster larvae still vrijlevende are caught and opgekweekt on mussel gauze. After three years of age in the then adult oyster parelmoerkorreltje are introduced, whereupon it still two up to three lasts before to see is if a pearl is formed.

The most known black pearl is Azra. She forms the heart in a collar of the Russian crown jewels.