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High-grade gold ore from the Harvard Mine, Jamestown, California, a wide quartz-gold vein in California's Mother Lode. Specimen is 3.2 cm (1.3 in) wide. Specimen is 3.2 cm (1.3 in) wide. Various theories of ore genesis explain how the various types of mineral deposits form within Earth's crust .
The lithosphere is the dominant reservoir of gold, containing an estimated 2.6x10 13 Mg. [1] Today, gold exists primarily as electrum, in hard rock deposits like tellurides, and as particles in placers in Earth's crust. Gold cycling starts with the microbial weathering of gold-bearing rocks and minerals which mobilizes gold in the environment ...
A miner underground at Pumsaint gold mine, Wales; c. 1938 Landscape of Las Médulas, Spain, the result of hydraulic mining on a vast scale by the Ancient Romans. The exact date that humans first began to mine gold is unknown, but some of the oldest known gold artifacts were found in the Varna Necropolis in Bulgaria.
Gold, a chemical element; Genomes OnLine Database; Global-scale Observations of the Limb and Disk, a NASA Explorer Mission of Opportunity; GOLD (parser), an open-source parser-generator of BNF-based grammars; Graduates of the Last Decade, an Institute of Electrical and Electronics Engineers program to garner more university level student members
Orogenic gold deposits are responsible for approximately 75% of the world's gold production at over 1 billion ounces, when accounting that the origin of many gold placer deposits were orogenic in nature. [25] [46] The price of gold at a given time will have an impact on whether a deposit will be economically feasible.
According to the World Gold Council, central banks purchased a record 483 tons of gold in the first half of the year. Central banks from Turkey, India, and China topped the list of the biggest buyers.
Gold occurs principally as a native metal, i.e., gold itself.Sometimes it is alloyed to a greater or lesser extent with silver, which is called electrum.Native gold can occur as sizeable nuggets, as fine grains or flakes in alluvial deposits, or as grains or microscopic particles (known as colour) embedded in rock minerals.
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