atomic number 12, magnesium, Mg - a light silver-white ductile bivalent metallic element; in pure form it burns with brilliant white flame; occurs naturally only in combination (as in magnesite and dolomite and carnallite and spinel and olivine)

mineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition

chrysolite - a brown or yellow-green olivine found in igneous and metamorphic rocks and used as a gemstone