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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.
Electrum. Electrum is a naturally occurring alloy of gold and silver, [1][2] with trace amounts of copper and other metals. Its color ranges from pale to bright yellow, depending on the proportions of gold and silver. It has been produced artificially and is also known as "green gold". [3]
Black Hills gold jewelry is a type of jewelry manufactured in the Black Hills of South Dakota. It was first created in the 1870s during the Black Hills Gold Rush by a French goldsmith named Henri LeBeau, who is said to have dreamed about the design after passing out from thirst and starvation. Black Hills gold jewelry depicts leaves, grape ...
Corinthian bronze (gold, silver) Cunife (nickel, iron) Cupronickel (nickel) CuSil (silver) Cymbal alloys (tin) Devarda's alloy (aluminium, zinc) Hepatizon (gold, silver) Manganin (manganese, nickel) Melchior (nickel); high corrosion resistance, used in marine applications in condenser tubes.
Orichalcum or aurichalcum / ˌ ɔːr ɪ ˈ k æ l k ə m / is a metal mentioned in several ancient writings, including the story of Atlantis in the Critias of Plato.Within the dialogue, Critias (460–403 BC) says that orichalcum had been considered second only to gold in value and had been found and mined in many parts of Atlantis in ancient times, but that by Critias's own time, orichalcum ...
Alloys containing palladium or nickel are also important in commercial jewelry as these produce white gold alloys. Fourteen-karat gold-copper alloy is nearly identical in color to certain bronze alloys, and both may be used to produce police and other badges. Fourteen- and eighteen-karat gold alloys with silver alone appear greenish-yellow and ...
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 ...
Gold, silver and bronze or copper were the principal coinage metals of the ancient world, the medieval period and into the late modern period when the diversity of coinage metals increased. Coins are often made from more than one metal, either using alloys, coatings (cladding / plating) or bimetallic configurations.