Why are Diamond Measures called “Carats”?

The carat is the  standard unit of weight for diamonds and other gemstones, and it comes from Carob seeds, which used to be used to weigh diamonds.   Carob seeds are small and had a fairly uniform weight, so that led early gem traders to drop them into their balance scales as  counterweights.  Today, we’re much more precise, and a carat is broken down into 100 “points” which represent smaller units; the pennies to a carat’s dollar, if you will.  A metric carat equals 0.200  or 1/5th g.  The USA adopted the carat as its standard in 1913.