Convert from carat [international] to quarter (ton) [US]

Unit Definition (carat [international])
The carat [international] is a unit of mass used for diamonds and other precious stones. Originally spelled karat, the word comes from the Greek keration, a carob bean; carob beans were used as standards of weight and length in ancient Greece in much the same way barleycorns were used in old England. Traditionally the carat was equal to 4 grains. The definition of the grain differed from one country to another, but typically it was about 50 milligrams and thus the carat was about 200 milligrams.

Unit Definition (quarter (ton) [US])
The quarter (ton) [US] is a traditional unit of weight equal to 1/4 hundredweight. In the U.S., "quarter" is also used informally to mean 1/4 ton, or 500 pounds (226.80 kilograms).