Hello, AU750 stands for: 18K gold, which means 75% gold and 25% other precious metals. This material is often used in mosaics. D0.083ct indicates the size of the main drill. D0.047ct represents the size of the accessory gem. As for the price, diamonds of this size are actually very cheap. If the price is only about 1000-2000, it is acceptable, but if it is a special style, the price will be higher.