Gold

No precious metal is as legendary and beautiful as gold. Gold has been used as a monetary standard throughout the history of mankind, and ancient gold jewellery and ornaments dating back many centuries are still found throughout the world.

Gold is the most malleable and ductile metal, and is easy to work with. It never tarnishes, and is unaffected by most chemicals. However, it becomes discoloured by chlorine, bleach, detergents, and certain hairsprays and cosmetics. Gold lacks resistance to pressure and easily bends. For this reason, all gold jewellery is alloyed with other metals to increase its toughness and durability.

USES
Gold is the most useful metal in the jewellery industry. Rings, bracelets, necklaces, earrings, and many other jewellery figures are fashioned from gold. Ancient gold masks and ornaments were used by many civilizations. Gold has also been used in coinage since the earliest of days.
"Picture Rock" (white Quartz with gold veins running through it) is sometimes polished into cabochons, creating a rare and unusual gem. Natural, water worn gold nuggets are sometimes made into pendants.

VARIETIES
The colour of pure gold is bright golden yellow. Besides for strengthening the gold, other metals may be alloyed with gold to give the gold distinct colour tinges. The different types of gold are based on the particular colour tinge:

	Rose Gold - Gold with a slightly reddish hue, caused by copper
	White Gold - Pale, almost silver-coloured gold, caused by nickel (and sometimes zinc or platinum)
	Green Gold - Gold with a slightly greenish hue, caused by copper and silver
	Blue Gold - Gold with a slightly bluish hue, caused by iron

The purity of the gold depends on the percentage of alloyed metal. This number is measured in karats. The karat measurement determines the percentage of gold to other metals on a scale of 1 to 24 , with 24 karats being pure gold. That means that 14 karat gold is only 14/24 (or 58.33%) gold. Gold with a high karat measurement is undesirable for jewellery because it is soft and bendable, and gold with a low karat measurement is undesirable because of its low gold content [hence lesser value].
Gold is one of the heaviest materials. The international weight measurement of gold is the troy ounce. One troy ounce of gold equals 31.1 grams.

FALSE NAMES
Fool's Gold - Miners term for Pyrite, which occurs together with gold and may resemble it in small flakes.

SIMILAR METALS
Many metallic alloys resemble gold. However, they can be easily distinguished from gold by analysis. Much gold-coloured jewellery is made out of cheap metals and coated with a very thin layer of gold. Such jewellery is known as "gold-plated". Through wear, the layer of gold erodes, exposing the cheaper metal.