Bicolor gold pendant and cultured pearl

Gold : Because of the softness of pure gold, it is alloyed with silver, copper or palladium. The proportion of these other metals give yellow, white gold. Without precision, the gold used in jewelry is 18 K, corresponding to 75% pure gold.
Carat : The carat (ct) is a unit of mass equal to 2 g. Carat is used for measuring the weight of gemstones.
Cultured pearls : Cultured pearls are the response of a pearl oyster to a man made tissue implant. This technique is used in Japan (Akoya pearls), in Australia, in Tahiti and China (fresh water pearl oysters).