Glass containing usually 3% to 4% of magnesium oxide. Electric lamp bulbs
have been mainly made from this type of glass since fully automatic
methods of production were adopted. CTD
A fine-grained metamorphic rock derived from a high-magnesium igneous
rock; e.g., serpentine. See also:hornfels
A limestone containing from 5% to 35% MgCO3 .
A crystalline variety of limestone containing not less than 5% nor more
than 40% of magnesium carbonate as the dolomite constituent.
A schistose metamorphic rock derived from a rock high in content of
magnesium; e.g., serpentine. See also:schist
magnesia ramming materials
Granular, airsetting mixtures, containing 70% to 80% MgO, used for
monolithic furnace linings.
An isometric mineral, MgCr2 O4 ; chromite series; spinel
group; forms series with spinel and with chromite; crystallizes in black
octahedra, but commonly massive. Also spelled magnochromite.
An isometric mineral, MgFe2 O4 ; magnetite series; spinel
group; strongly ferrimagnetic. Also spelled magnoferrite.
A magnesian variety of laumontite.
A trigonal mineral, MgCO3 ; calcite group; rhombohedral cleavage;
in veins in serpentinite and peridotite, magnesium-rich schist, and
altered dolomitic marbles. Syn:giobertite; magnesium carbonate.
Common term for ground magnesite.
A refractory material, fired or chemically bonded, consisting essentially
of dead-burned magnesite; the MgO content usually exceeds 80%. Such
refractories are used in the hearths and walls of basic steel furnaces,
mixer furnaces, and cement kilns. Dodd
A light, silvery-white, and fairly tough metal. Symbol, Mg. It does not
occur uncombined, is found in large deposits in the form of magnesite,
dolomite, and other minerals. Readily ignites upon heating. Used in
flashlight photography, flares, and pyrotechnics, including incendiary
bombs. Its alloys are essential for airplane and missile construction.
Handbook of Chemistry and Physics, 3
MgAl2 O4 ; melting point, 2,135 degrees C; sp gr, 3.6;
thermal expansion (100 to 1,000 degrees C), 9.0 X 10-6 . This
compound is the type mineral of the spinel group. See also:spinel
A smectite with exchangeable magnesium.