Gold

From Encyclopediak

Gold, a precious metal, which, on account of its luster and resistance to oxidation, has always been used in ornamentation and as money. Gold is found in quartz veins in the oldest rocks and in the sand of most river beds. It is estimated that there is two cents worth of gold in every ton of sea water. Gold is found in association with lead, silver and copper, and many processes for separating it from its alloys are now in use. See Metallurgy.

Gold is a relatively soft, reddish-yellow metal of such ductility that it can be drawn into exceedingly fine wire threads and beaten into very thin leaves. The light passing through these leaves has a greenish tinge, and gold when melted is a greenish liquid. Gold does not tarnish in air even when heated, and is attacked by only one single acid, selenic, or by the compound nitric-muriatic acid, called aqua regia. It is also soluble in potassium cyanide. Gold is so soft and wears away so rapidly that it is seldom, if ever, used pure, but generally in alloy with copper or silver. With the former it has a tinge of red, and with the latter a paler gold color. American gold coins are 90 percent gold and 10 percent copper. Goldsmiths estimate the purity of gold in carats, 24 carats being pure gold. Most jewelry is from 14 to 18 carats fine. Gold is used everywhere for the choicest ornaments and ranks in this respect with the precious stones. It is also the standard for money in all civilized countries. The chief gold-producing countries are South Africa, United States, Australia, Mexico, Canada and Russia. The annual production of gold in the world is about 350,000,000. Of this amount the United States produces about 96,000,000, Africa about 175,000,000 and Australia about 65,000,000. The leading gold-producing states of the United States are California, Colorado, Nevada and South Dakota.