MEASURING GOLD
INDICATIONS OF PURITY. When we use the word carat we refer to the purity ol gold. It is an international standard measurement which was suggested first in 1905. and was in general use by 1914. Twentyfour carat would be pure gold: 22 carat gold would contain 22 parts of geld to 2 of copper; 18 carat. 18 parts of gold to 6 of copper, and so on. The gold of sovereigns and of the best goldware is 22 carat—that is standard gold. Pure gold is soft for making coins or ornaments. If sovereigns were made of pure gold, they would wear away very quickly. To make gold harder, it is alloyed with silver and copper. Silver makes the colour paler: copper makes it redder. If you compare the colour of a good gold ring or watch chain, you will find a difference in their colours. Nearly all metals can be dissolved in strong acid, but gold cannot. Therefore gold is called a noble metal, or even the king of metals. A mixture of two strong acids, which is known as aqua regia—that is. kingly water —will however, dissolve even gold.
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Wairarapa Times-Age, 24 May 1940, Page 3
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192MEASURING GOLD Wairarapa Times-Age, 24 May 1940, Page 3
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