Pewter is a malleable metal alloy, traditionally 85–99% tin, with the remainder consisting of copper, antimony, bismuth and sometimes, less commonly today, lead. Silver is also sometimes used. Copper and antimony act as hardeners while lead is common in the lower grades of pewter, which have a bluish tint. It has a low melting point, around 170–230 °C (338–446 °F), depending on the exact mixture of metals. The word pewter is likely a variation of the word spelter, a term for zinc alloys (originally a colloquial name for zinc).