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The chemical element gold,
atomic number 79, symbol Au (from the Latin aurum), is a
soft, lustrous yellow, malleable metal. It is one of the
transition metals and its atomic weight is 196.967; it
belongs to group 1B in the periodic table along with copper
and silver. Although the Earth's crust averages a mere 0.004 grams of gold per ton, commercial concentrations of gold are found in areas distributed widely over the globe. Gold occurs in association with ores of copper and lead, in quartz veins, in the gravel of stream beds, and with pyrites (iron sulfide). Seawater contains astonishing quantities of gold, but the process of recovery is not economical. The distribution of gold seems to validate the theory that gold was carried toward the Earth's surface from great depths by geologic activity, perhaps with other metals as a solid solution within molten rock. After this solid solution cooled, its gold content was spread through such a great volume of rock that large fragments were unusual; this theory explains why much of the world's gold is in small, often microscopic particles. The theory also explains why small amounts of gold are widespread in all igneous rocks; they are rarely chemically combined and seldom in quantities rich enough to be called an ore. Because of its poor chemical reactivity, gold was one of the first two or three metals (along with copper and silver) used by humans in these metals' elemental states. Because it is relatively unreactive, it was found uncombined and required no previously developed knowledge of refining. Gold was was probably used in decorative arts before 9000 BC. Even civilizations that developed little or no use of other metals prized gold for its beauty If you are looking for gold and can not tell the difference between the second photo, of pyrite on a gold nugget, then you will find lots of pyrite, but no gold. Pyrite is referred to as "Fools Gold", since many a prospector brought home the shiny Iron Sulfate, and staked claims on their "gold " deposit, which turned out to be pyrite. All that glitters is not gold. Back to Top |
Pyrite on top of gold nugget.
Oxide gold ore, assaying 5-15 oz Au/ton ore.
