A diamond’s weight is measured in carats – the standard unit of weight used for gemstones. 1 carat = 0.2 grams, or 200milligrams. The higher the carat, the more rare and valuable the diamond.
Diamonds are priced in various carat weight brackets. Carat weight alone has the greatest impact on price when the rest of the 4Cs are equal. It increases exponentially at certain weights. The most popular carat weight brackets are 0.50ct, 0.75ct, and 1.00ct. Each carat can be subdivided into 100 'points.' This allows very precise measurements to the hundredth decimal place. Diamond weights greater than one carat are expressed in carats and decimals.
Where does the term “Carat” come from?
The original of the term “carat” comes from the carob seed. Carob seeds were historically used as counter weights due to their uniform size, shape and roughly equivalent mass. Carat Weight was standardised as 0.2 grams in the early 20th century.