Nonmetallic Minerals

noncombustible solid rocks or minerals used in industry and construction in natural form or after mechanical, thermal, or chemical processing or for the extraction of nonmetallic elements or their compounds.

The variety of the composition and properties of nonmetallic minerals determines the complex nature of their use. Nonmetallic minerals are ordinarily divided into four groups on the basis of the field in which they are used: (1) chemical raw materials (apatite, halite, sylvinite, carnallite, bischofite, polyhalite, native sulfur, sulfur pyrite, celestite, barite, borosilicates, nitrates, natural salt, and so on), most of which are used to produce mineral fertilizers; (2) metallurgical raw materials, including nonmetallic minerals used to produce refractories (refractory clays, dolomite, magnesite, quartzite, and so on), as fluxes (limestones, dolomites, quartzites, and fluorite) and molding materials (molding clays and sands), and agglomerations of fine ore (bentonite clays); (3) construction materials, including nonmetallic construction materials (granite, labradorite, diorite, limestone, dolomite, marble, quartzite, tuff, sandstone, and so on), ceramic and glass raw materials (high-melting clays, sands, kaolins, feldspar, wollastoite, and rhyolites), raw material for the production of binders (low-melting clays, limestone, and marl), mineral dies (ochers and colcothar), and thermal and acoustic insulation materials (perlite and vermiculite); (4) nonmetallic nonore raw materials, represented by the industrial crystals (diamond, piezo quartz, Iceland spar, muscovite, phlogopite, and agate) and precious and semiprecious stones (jewelry diamond, emerald, topaz, ruby, agate, malachite, turquoise, jasper, and amber). Asbestos, talc, graphite, and abrasive materials (corundum and emery) are also ordinarily classed with this group.

As technology develops, the group of nonmetallic minerals is growing steadily through industrial use of rocks and minerals not formerly used in industry (perlite and wollastonite).