18-karat green gold alloy compositions

摘要

An improved 18-karat green gold alloy composition comprises about 75.0% gold; about 6.0-7.0% silver; about 9.0-11.7% copper; and about 6.5-9.0% zinc. The improved alloys are capable of being age-hardened to a hardness of about 240 VHN by being heated to about 550° F. for about one hour, and thereafter being permitted to cool in air. The hard-nesses of the alloys are reversible between their aged-hardness and annealed-hardness values. The color of said composition is between about -1.5 to about -3.0 CieLab a* color units, and between about 19 to about 26 CieLab b* color units.