unit of measure

汉语翻译

例句：

1. A unit of measure for the fineness of gold, equal to!/24 part. Pure gold is24 karat; gold that is50 percent pure is12 karat.
   开测量黄金纯度的单位，等于24等分中的一分。纯金为24开; 50％纯度的黄金为12开