White gold :
White gold is an alloy of pure gold with copper, Zinc, Palladium or nickel.
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).