Gold

Gold was one of the first metals to be mined because of its native form. It is imperishable and a very beautiful element. It is also not combined with other elements and can be made into very nice objects. Ancient Egypt was a great example on how gold could be used. Egypt used gold to show other parts of the world their dominance. Hallways, buildings, and tombs were always decorated in Gold. It is said that ancient civilizations obtained their gold from various deposits in the middle east. Most of the gold used by the ancient Egyptian pharaohs was found by the Nubian desert and Red sea. Gold has many uses it is used for money, jewelry, dentistry, arts and other medical uses. The basic unit of weight used in dealing with gold is the troy ounce. One troy ounce is equivalent to 20 troy pennyweights. In the jewelry industry, the common unit of measure is the pennyweight (dwt.) which is equivalent to 1.555 grams. Gold is relatively scarce in the earth, but it occurs in many different kinds of rocks and in many different geological environments. Though scarce, gold is concentrated by geologic processes to form commercial deposits of two principal types: lode (primary) deposits and placer (secondary) deposits. One widely accepted hypothesis proposes that many gold deposits, especially those found in volcanic and sedimentary rocks, formed from circulating ground waters driven by heat from bodies of magma (molten rock) intruded into the Earth’s crust within about 2 to 5 miles of the surface. Another hypothesis suggests that gold-bearing solutions may be expelled from magma as it cools, precipitating ore materials as they move into cooler surrounding rocks. This hypothesis is applied particularly to gold deposits located in or near masses of granitic rock, which represent solidified magma. Geologists examine all factors controlling the origin and emplacement of mineral deposits, including those containing gold. Igneous and metamorphic rocks are studied in the field and in the laboratory to gain an understanding of how they came to their present location, how they crystallized to solid rock, and how mineral-bearing solutions formed within them. Studies of rock structures, such as folds, faults, fractures, and joints, and of the effects of heat and pressure on rocks suggest why and where fractures occurred and where veins might be found.

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