The brightness and ornamental beauty of gold have fascinated humans for at least 5,500 years and still do. This noblest metal takes its name from the germanic “gulth,” meaning glowing or shining metal. gold is also a “precious metal” - this means that it is rare with high economic value.
Gold established the standard by which wealth is measured. Gold is sometimes found free in nature but it is generally found in conjunction with silver. It is usually alloyed with other metals, such as silver, copper, platinum or palladium, to increase its strength. Gold alloys are used to make jewelry, decorative items, dental fillings, and coins. Gold is a good conductor of heat and electricity and doesn’t tarnish when it is exposed air, so it can be used to make electrical connectors and printed circuit boards.
Gold is also a good reflector of infrared radiation and can be used to help shield spacecraft and skyscrapers from the sun’s heat. gold-coated mirrors can be used to make telescopes that are sensitive to infrared light. gold is the most malleable and ductile (can be drawn into a very thin wire) of all known metals. A single ounce of gold can be beaten into a sheet measuring roughly 5 meters on aside.
Pure gold is soft. On a scale of 1 to 10, it has an average hardness of 2.8; diamond is 10. gold alloyed with other metals becomes harder. gold has a specific gravity of 19.3, meaning it is more than 19 times heavier than an equal volume of water.
This property is very useful in the recovery of placer gold. Gold has a rich yellow color or “kindly” appearance, turning paler as its silver content increases. gold is relatively easy to identify when you know its properties, but novices can confuse it with minerals such as pyrite and mica. Both can occur with gold. Pyrite, or “fool’s gold,” is brassy light yellow, and brittle. Mica is light yellow to bronzy, lightweight, and has a platy appearance.
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