<P> A native metal is any metal that is found in its metallic form, either pure or alloyed, in nature . Metals that can be found as native deposits singly or in alloys include aluminium, antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, molybdenum, nickel, rhenium, selenium, tantalum, tellurium, tin, titanium, tungsten, vanadium, and zinc, as well as two groups of metals: the gold group, and the platinum group . The gold group consists of gold, copper, lead, aluminium, mercury, and silver . The platinum group consists of platinum, iridium, osmium, palladium, rhodium, and ruthenium . Amongst the alloys found in native state have been brass, bronze, pewter, German silver, osmiridium, electrum, white gold, and silver - mercury and gold - mercury amalgam . </P> <P> Only gold, silver, copper and the platinum metals occur in nature in large amounts . Over geological time scales, very few metals can resist natural weathering processes like oxidation, which is why generally only the less reactive metals such as gold and platinum are found as native metals . The others usually occur as isolated pockets where a natural chemical process reduces a common compound or ore of the metal, leaving the pure metal behind as small flakes or inclusions . </P> <P> Non-metallic elements occurring in the native state include carbon and sulfur . Silicon, a semi-metal, has been found in the native state on rare occasions as small inclusions in gold . </P>

Where are they located and why are they found only in those places