Molybdenum: A
rare, hard, silver-white metal having a very high fusing point. It is
used as an alloy for hardening steel, as the supports for the lower
ends of tungsten filaments in electric lamps, and for making ribbons
used in electric furnaces. It is also used as fireproofing, and for
coloring leather and rubber. Molybdenum salts are important chemicals.
Monazite: Phosphate
of Cerium metals. Although it occurs as small grains and crystals in
granite, it is found in commercial quantities only in the sands of
streams. Color gray, yellow, reddish or brown. This mineral is the chief source of
Thorium Oxide used in the manufacture of gas mantles. The most
important occurrences are in southeastern Brazil, and in the
Appalachian Mts. from North Carolina into South Carolina.
Moonstone: A
translucent variety of Adularia, which shows a shimmering light that
sometimes takes on a bluish tinge. The stones showing the bluish
reflections are
considered the choicest. These are found in Ceylon and are much
admired as a gem stone.
Moss
Agate: A variety of Agate filled with brown moss-like or dendritic
forms of chlorite, which is sometimes mixed with sesquioxide of iron,
distributed through the mass in very fine and intricate patterns. It is
used as an ornamental stone.
Mottramite: A
Vanadate of Lead and Copper. Lead 57.2%, Copper 20.4%. Occurs in thin
crystalline incrustations and occasionally in distinct crystals. Color
velvety black, and in thin sections, yellow. It occurs at Mottram,
St. Andrews, Cheshire, England.
Muscovite: The
most common and at the same time the most important of the Micas,
occurring in large crystals, small flakes or scaly masses. It is
colorless or some light shade of green, yellow or red. Lepidolite is
the rose-red variety. Muscovite is used in two forms, as sheet mica and
as ground mica. The sheet mica is used in making gas lamp chimneys,
lamp shades and windows in stoves; also as insulators in electrical
appliances. Ground mica is used in the manufacture of wall paper, heavy
lubricants and fancy paints. It is mined in North Carolina, South
Dakota, New Hampshire, Virginia, and other states.
Nadorite: Chloride
of Lead and Antimony. Lead 52.4%, Antimony 30.5%. Occurs in crystals,
both tabular and prismatic, smoky-brown to brownish-yellow in color. It
is found in Algeria, at Djebel-Nador, from which it takes its name
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