*DWT
A pennyweight (dwt) is a unit of mass. Jewellers use the pennyweight in their calculations for the necessary amount of precious metals in casting items using the lost-wax casting process. It is the common weight used in the valuation of precious metals. Dentists and dental labs still use the pennyweight as the measure of precious metals in dental crowns and onlays. While "dwt" is the most common abbreviation for pennyweight (as "d" was the abbreviation for "penny" in the pre-decimalisation British system), some sources list "pwt" as an alternative.