Goldschmidt classification

The Goldschmidt classification, developed by Victor Goldschmidt, is a geochemical classification which groups the chemical elements within the Earth according to their preferred host phases into lithophile (rock-loving), siderophile (iron-loving), chalcophile (ore-loving or chalcogen-loving), and atmophile (gas-loving) or volatile (the element, or a compound in which it occurs, is liquid or gaseous at ambient surface conditions).

Some elements have affinities to more than one phase. The main affinity is given in the table below and a discussion of each group follows that table.

Trace elements having an abundance much less than the one part per trillion of Ra and Pa (namely Tc, Pm, Po, At, Rn, Fr, Ac, Np, and Pu) are shown as synthetic, because their occurrence in nature is fleeting and is entirely dependent on their long-lived parents Th and U, and are not very mobile. For instance, polonium's chemistry would predict it to be a chalcophile, but in actuality it tends to occur instead as a lithophile along with its parent uranium. When needed, these elements are typically produced synthetically in nuclear reactors instead of using the tedious and laborious process of extraction from uranium ores.

Lithophile elements are those that remain on or close to the surface because they combine readily with oxygen, forming compounds that do not sink into the core. The lithophile elements include:Al, B, Ba, Be, Br, Ca, Cl, Cr, Cs, F, I, Hf, K, Li, Mg, Na, Nb, O, P, Rb, Sc, Si, Sr, Ta, Th, Ti, U, V, Y, Zr, W and the lanthanides.

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