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Bronze disease is the chloride corrosion of cuprous (copper-based) artifacts. It was originally thought to be caused by bacteria. [ 1 ] It is contagious in that the chlorides which cause it can spread the condition if they are brought into contact with another cuprous object. Despite its name, bronze disease can affect any copper-bearing alloy ...
Design date. 1798. The Draped Bust dollar is a United States dollar coin minted from 1795 to 1803, and was reproduced, dated 1804, into the 1850s. The design succeeded the Flowing Hair dollar, which began mintage in 1794 and was the first silver dollar struck by the United States Mint. The designer is unknown, though the distinction is usually ...
Design date. 2009–present. The Sacagawea dollar (also known as the " golden dollar ") is a United States dollar coin introduced in 2000, but subsequently minted only for niche circulation from 2002 onward. The coin generally failed to meet consumer and business demands. It is still generally accepted in circulation.
In 1795-1797, a scrawny, naturalistic bald eagle was depicted on the reverse side of all silver coins. This design is known as Draped Bust, Small Eagle and usually commands a high price due to the extremely low mintage at the time. In 1798, the small eagle was replaced by the Heraldic eagle. This design is known as Draped Bust, Heraldic Eagle.
The Susan B. Anthony dollar is a United States dollar coin minted from 1979 to 1981, when production was suspended due to poor public acceptance, and then again in 1999. . Intended as a replacement for the larger Eisenhower dollar, the new smaller one-dollar coin went through testing of several shapes and compositions, but all were opposed by the vending machine industry, a powerful lobby ...
Renaissance Wax is also commonly used in the preservation of bronze and copper coins. The wax seals the coins and helps prevent deterioration from moisture and air exposure. It may [citation needed] also help prevent the onset of the chloride-related corrosion commonly called bronze disease, although it won't arrest this once started.
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.
Ptolemaic coinage. A silver tetradrachm of Ptolemy IV Philopator (r. 221 – 205 BC); an undated issue from the Arados royal mint, struck c. 214–212 BC, 26 mm in width, 14.10 gm in weight; the obverse shows a diademed head of Ptolemy I Soter wearing the aegis, while the reverse shows an eagle standing on a thunderbolt with a Greek inscription ...