Sapphire and Diamonds

The grain is the system of weight that was based on, simply enough, the wheat grain (or the barley grain in some ancient cultures). The grain was the equivalent of 1/4th of a carat, or, more simply, one carat equaled approximately 4 grains. From this use of the grain, you can see that the ancients understood the need for a quantifiable and standard system of weight. The tiny weight measurements involved with the grain further demonstrates their understanding of the need for weight that could accurately and consistently give a weight measurement for diamonds.