How to Obtain
- Obtained randomly through lot in Campaign Unions
Pearls are hard objects valued as gemstones (one of the few organic gemstones) which are produced inside oysters (sessile, shelled mollusks) by secreting nacre to cover some invasive body inside them (a grain of sand, or small organism, like a parasite) due to that body irritating their tissues. Nacre (AKA mother-of-pearl) is a combination of aragonite or calcite (each a crystalline polymorph of calcium carbonate) bound by conchiolin, an organic adhesive. The pearl forms over the process of a few years and only rarely does it naturally produce a spherical form. Pearls can range in color from white to cream or pink (occasionally with a tint of various other colors), but are always iridescent.
While all oysters and many mollusks can produce pearls, only one family of oysters is used for harvesting pearls, family Pteriidae (the pearl oysters), more specifically, genus Pinctada; family Ostreidae (oysters, true oysters) are not used (they are mainly used for food).
Pearls were a rare gemstone prior to the 20th century, when the advent of cultured pearls, pearls made by gathering oysters and intentionally inserting a small object (usually a rounded piece of shell) to produce a pearl of the desired shape (i.e. a sphere), developed. Most pearls were originally from the Far East (China & Japan).