A mineral is a naturally occuring, homogeneous, solid with a crystalline atomic structure. Crystallinity implies that a mineral has a definite and limited range of composition, and that the composition is expressible as a chemical formula. Some definitions of minerals give them as inorganic materials, however both diamonds and graphite are considered minerals, and both are primarily comprised of carbon, which would make them organic. So this leads me, as an engineer, to believe that mineralogists do not have a good, precise definition of a mineral, but rather a loose definition. The definition above, is the most inclusive and would include all substances currently described as minerals. The key items that make something a mineral are occurring naturally, and the definite crystal structure, that is expressible as a chemical formula. Rocks that do not meet this criteria are referred to as amorphis - not having a definite structure or expressible as a chemical formula. Some elements that occur naturally and are minerals are arsenic, bismuth, platinum, gold, silver, copper, and sulphur.
THE DEFINITION OF ORGANIC: Organic chemistry is the study of those substances containing carbon in combination with hydrogen (H), and a few other non metals, namely oxygen (O), nitrogen (N), sulfur (S) and the halogens (F2, Cl2, Br2, and I2).
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The Mineral, Wolframite, is a principal ore of tungsten. It is a iron and manganese tungstate mineral.
It is monoclinic, with tabular crystals, has a hardness of 5 to 5.5 mhos, SG of 7.1 to 7.5, is dark gray,
reddish brown, brownish black, or iron black in color. Streak is dark red brown or black. Wolframite is commonly found in granite and pegmatite dikes, and is often associated with cassiterite; it also occurs in sulfide veins and placer deposits. Because heat causes tungsten to expand at about the same rate as glass, the metal is widely used to make glass-to-metal seals. Tungsten or its alloys are used for filaments for electric lamps, electron and television tubes, electrical contact points for automobile distributors, heating elements for electrical furnaces, and space, missile, and high-temperature applications. Tungsten carbide is an important compound in the metal working, mining, and petroleum industries. Alloys such as high-speed steel, cristite, and stellite, used in high-speed tools, contain tungsten. Other important tungsten compounds are calcium and magnesium tungstates, which are used in fluorescent lighting, and tungsten disulfide, which is used as a high-temperature lubricant at temperatures up to 500 deg C. Tungsten compounds also find uses in the chemical, paint, and tanning industries. |