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Amongst the alloys made of gold, silver, and copper, the hardest is the 18.1 K pink gold (75.7% gold and 24.3% copper). An alloy with only gold and silver is the hardest at 15.5 K (64.5% gold and 35.5% silver). During ancient times, due to impurities in the smelting process, gold frequently turned a reddish color.
The earliest gold artifacts were discovered at the site of Wadi Qana in the Levant. [13] Silver is estimated to have been discovered in Asia Minor shortly after copper and gold. [14] There is evidence that iron was known from before 5000 BC. [15] The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in ...
Hepatizon (Greek etymology: ἧπαρ, English translation: "liver"), also known as black Corinthian bronze, was a highly valuable metal alloy in classical antiquity.It is thought to be an alloy of copper with the addition of a small proportion of gold and silver (perhaps as little as 8% of each), mixed and treated to produce a material with a dark purplish patina, similar to the colour of liver.
Electrum was often referred to as "white gold" in ancient times but could be more accurately described as pale gold because it is usually pale yellow or yellowish-white in color. The modern use of the term white gold usually concerns gold alloyed with any one or a combination of nickel, silver, platinum and palladium to produce a silver-colored ...
Tumbaga is an alloy composed mostly of gold and copper. It has a significantly lower melting point than gold or copper alone [citation needed]. It is harder than copper, but maintains malleability after being pounded. Tumbaga can be treated with a carboxylic acid, such as oxalic acid, to dissolve copper off the surface. What remains is a shiny ...
Drawing a line with gold on a touchstone will leave a visible trace. Because different alloys of gold have different colors (see gold), the unknown sample can be compared to samples of known purity. This method has been used since ancient times. In modern times, additional tests can be done.
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Guanín objects made by the Taínos excavated in Cuba.. Guanín is an alloy of copper, gold and silver, similar to red gold, used in pre-Columbian central America. [1] The name guanín is taken from the language of the Taíno people, who prized it for its reddish color, brilliant shine, and unique smell, and associated it with both worldly and supernatural power.