West Chester, Pa., in massive, fibrous and foliated forms and in various colors.
Witherite: Barium
Carbonate. Baryta 77.7%, Carbon Dioxide 22.3%. It occurs in crystals
(repeated twins); also in globular and tuberose forms, white, yellowish
or grayish, in color. This is not a very common mineral in the United
States but occurs in large quantities in England, where some of the
crystals measure as much as six inches in length. Witherite is used to
some extent as a source of Barium compounds.
Wolframite: Tungstate
of Iron-Manganese. Composition varies. This mineral occurs in crystals
tabular and prismatic and often bladed; also coarse columnar and
granular massive, color dark gray, brown and brownish-red. It occurs in
all tin-producing districts, especially at Zinnwald and Schneeberg,
Saxony; in Siberia; Cornwall, Eng.; Bolivia and New South Wales, and
many places in the United States.
Its
chief use is to furnish tungsten used in the manufacture of tungsten
steel, and as a source of tungsten salts employed in dyeing. (See
Tungsten.)
Wollastonite:
Calcium Metasilicate. Silica 52%, Lime 48%. Occurs in tabular and
prismatic crystals; massive to fibrous; also compact. Color,
grayish-white, yellow,
red or brown. It is found in Bavaria, Italy, Greece, Hungary; also
in Diana, New York, and at Keweenaw Point, Michigan. Named
after W. H. Wollaston, English Physicist.
Wulfenite: Lead
Molybdate. Molybdenum Trioxide 39.3%, Lead Oxide 60.7%. Calcium
sometimes replaces the lead. This, the only Molybdate of importance
that occurs as a mineral, is found tabular, prismatic and as pyramidal
crystals. Coloi wax-yellow passing to orange-yellow; also olive-green,
yellowish-gray, grayish-white to nearly colorless; also orange to
bright red.
It
occurs in all lead localities in Europe; and in the United States near
Phoenixvflle, Pa.; in the Organ Mts., Utah; in Arizona; and in many
lead mines in the Rocky Mountain States. It is an important source of
Molybdenum, but because of the few uses to which this metal is put, the
amount of Wulfenite mined is very small.
Wurtzite: Zinc
Sulphide. Sulphur 33%, Zinc 67%. This mineral occurs in brownish-black
crystals, in masses, and in fibers. In chemical and physical
properties, this mineral
resembles Sphalerite. The crystals are frequently observed as furnace
products.
