Pink colored metal alloy having low gold content

Abstract

Pink colored metal alloys have a low gold content. The pink colored metal alloys of the present disclosure display a high level of tarnish resistance during extended use and wear, and have the appearance and properties comparable 10 karat (or above) gold alloys, which have a significantly higher gold content.

What is claimed is: 
     
         1 . A pink colored metal alloy comprising, by weight percent with respect to the total weight of the alloy: about 33.0% to about 20.0% Au; about 60.0% to about 45.0% Cu;
 about 14.8% to about 2.5% Ag; and 0% to about 5.0% Zn.   
     
     
         2 . The alloy of  claim 1 , further comprising from about 0.001 to about 1% X, wherein X is one or more elements selected from the group consisting of silicon, germanium, cobalt, iridium, ruthenium, boron, and mixtures thereof. 
     
     
         3 . The alloy of  claim 2 , wherein X is silicon and germanium. 
     
     
         4 . The alloy of  claim 3 , wherein the weight percent of X from about 0.1% to about 0.3%. 
     
     
         5 . The alloy of  claim 2 , wherein X is silicon. 
     
     
         6 . The alloy of  claim 2 , wherein X is germanium. 
     
     
         7 . The alloy of  claim 1 , wherein the weight percent of the Au is from about 32% to about 25%. 
     
     
         8 . The alloy of  claim 1 , wherein the weight percent of the Cu is from about 56.0% to about 54.0%. 
     
     
         9 . The alloy of  claim 1 , wherein the weight percent of the Ag is from about 12.8% to about 10.8%. 
     
     
         10 . The alloy of  claim 1 , wherein the weight percent of the Zn is from about 0.8% to about 1.2%. 
     
     
         11 . A pink colored metal alloy comprising: gold, copper, zinc and silver, wherein the gold is present in an amount of from about 33.0% to about 20.0% by weight percent with respect to the total weight of the alloy; and ratios of the percentage by weight, with respect to the weight content of gold, copper, zinc and silver only, of copper:silver and copper:zinc are from about 15.0(Cu):1.0(Ag) to about 3.0(Cu):1.0(Ag) and from about 70(Cu):1.0(Zn) to about 15(Cu):1.0(Zn), respectively. 
     
     
         12 . The alloy of  claim 11 , further comprising from about 0.001 to about 1% X by weight percent with respect to the total weight of the alloy, wherein X is one or more elements selected from the group consisting of silicon, germanium, cobalt, iridium, ruthenium, boron, and mixtures thereof. 
     
     
         13 . The alloy of  claim 12 , wherein X is silicon and germanium. 
     
     
         14 . The alloy of  claim 13 , wherein the weight percent of X from about 0.1% to about 0.2%. 
     
     
         15 . The alloy of  claim 12 , wherein X is silicon. 
     
     
         16 . The alloy of  claim 12 , wherein X is germanium. 
     
     
         17 . The alloy of  claim 11 , wherein the weight percent of the gold is from about 32% to about 25%. 
     
     
         18 . The alloy of  claim 11 , wherein the weight percent of the copper is from about 56.0% to about 54.0%. 
     
     
         19 . The alloy of  claim 11 , wherein the weight percent of the silver is from about 12.8% to about 10.8%. 
     
     
         20 . The alloy of  claim 11 , wherein the weight percent of the zinc is from about 0.8% to about 1.2%.