- Metal with symbol Mg - Metallic element - A light silver-white metallic element, malleable and
ductile, quite permanent in dry air but tarnishing in moist air. It
burns, forming (the oxide) magnesia, with the production of a blinding
light (the so-called magnesium light) which is used in signaling, in
pyrotechny, or in photography where a strong actinic illuminant is
required. Its compounds occur abundantly, as in dolomite, talc,
meerschaum, etc. Symbol Mg. Atomic weight, 24.4. Specific gravity,
1.75.