native element[′nād·iv ′el·ə·mənt]
any of the chemical elements encountered in nature in the form of more or less stable minerals. Native elements are classified as nonmetals (polymorphic modifications of carbon—diamond and graphite—native S, Se, Te), semimetals (native As, Sb), and metals (native Au, Ag, Cu, Pt, Pd, Ir, Fe, Ta, Pb, Zn, Sn, Hg, Bi). Since the solid solutions of native metals are mineralogically and genetically closely related to the metals, they are usually grouped with native elements, as are, sometimes, intermetallic compounds. For example, minerals of the platinum group include, in addition to rare platinum itself, ferroplatinum and polyxene. Gases that exist in an uncombined state in nature include nitrogen, oxygen, hydrogen, argon, helium, krypton, xenon, and radon.
Most native elements are rarely encountered, and only under unusual conditions do they form large aggregations (deposits). Of the metals, native gold and elements of the platinum group have great industrial importance. Native copper, which is a component of ores in several types of deposits, is less important to industry, and native silver has even less significance. Of the nonmetals, diamond, graphite, and sulfur have great importance. Native iron and nickeliferous iron occur in lunar rock and meteorites but are rarely found in the earth’s crust.
Polymorphic modifications are typical of certain minerals making up the native elements. Native elements, like all minerals, are characterized by the presence of admixtures and by a variety of forms, both of which reflect the conditions under which the native elements were formed. The origin of native elements derives from magmatic, hydrothermal, metamorphic, and supergene processes. Many native elements are found in placers.
REFERENCEMineraly: Spravochnik, vol. 1. Moscow, 1960.
A. S. MARFUNIN