metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.

carnallite - a white or reddish mineral consisting of hydrous chlorides of potassium and magnesium; used as a fertilizer and as a source of potassium and magnesium

dolomite - a light colored mineral consisting of calcium magnesium carbonate; a source of magnesium; used as a ceramic and as fertilizer

magnesite - a black magnetic mineral consisting of magnesium carbonate; a source of magnesium

olivine - a mineral consisting of magnesium iron silicate; a source of magnesium

magnesia, magnesium oxide, periclase - a white solid mineral that occurs naturally as periclase; a source of magnesium

spinel - a hard glassy mineral consisting of an oxide of magnesium and aluminum; occurs in various colors that are used as gemstones