Gold has superior electrical conductivity and resistance to corrosion. Worldwide, there are two types of gold deposits. In situ or lode deposits are disseminations of metallic gold in quartz veins, traces of gold contained in certain sulfide minerals, or extremely fine-grained particles dispersed in host rocks. Placer deposits form from weathering and erosion of rocks containing gold. Secondary gold concentrations result due to the metal's high specific gravity.
Placer gold exists as fines, scales, flakes, grains, and nuggets.
Native gold usually contains variable amounts of silver. Gold is used several ways, but over half the world's yearly consumption is in jewelry and artwork. In jewelry, pure gold is alloyed with copper and silver to increase its hardness. Gold has emerged in the late 20th century as an essential industrial metal, used in computers, communication equipment, spacecraft, jet airplane engines, and many other applications. In the early 1880's, reports and rumors of gold finds in Arkansas prompted an investigation by the Arkansas Geological Survey.