They are the only gemstone that comes naturally from a living creature, and needs no intervention by man to show of it's luminous beauty.
Freshwater pearls are now almost always "farmed" known as cultured pearls, they are started off by introducing an irritant (speck of dirt) to an oyster and the oyster does the rest by releasing layers and layers of nacre, that nacre then hardens and creates a beautiful original pearl. The bigger the pearl the longer the oyster had to keep depositing nacre.
We love pearls and offer this advise, let them be the last thing you put on before you go out and the first thing you take off when you get home, hairspray and perfume can dull the beauty of pearls, so be kind to them.
Also, have you ever noticed how "collected" women look when dressed in pearls - I'm only saying!