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QUARTZ

Silica refers to naturally occurring minerals composed principally of silicon dioxide (SiO2). Silicon dioxide exists in both crystalline and amorphous forms. Quartz, cristobalite and tridymite are the three most common crystalline forms. These forms are interrelated and can change their form under different conditions of temperature and pressure. There are two different forms of quartz that are designated by the prefixes alpha and beta. The most common form is alpha-quartz which is a major component of igneous rocks, such as granite and pegmatite, but is also found in sandstone and sedimentary rock such as slate and shale. Beta-quartz is less common. Quartz is the most common mineral on the face of the Earth. It is made up of a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. It forms at all temperatures. It is abundant in igneous, metamorphic and sedimentary rocks. It is highly resistant to both mechanical and chemical weathering. This durability makes it the dominant mineral of mountaintops and the primary constituent of beach, river and desert sand. Quartz is one of the most useful natural materials. Its usefulness can be linked to its physical and chemical properties. It has a hardness of seven on the Mohs Scale which makes it very durable. It is chemically inert in contact with most substances. It has electrical properties and heat resistance that make it valuable in electronic products. Its luster, color and diaphaneity make it useful as a gemstone and also in the making of glass.

PROPERTIES

i. COLOR: Quartz occurs in virtually every color. Common colors are clear, white, gray, purple, yellow, brown, black, pink, green, red.

ii. STREAK: Colorless

iii. LUSTER: Viterous

iv. CLEAVAGE: None

v. HARDNESS: 7

vi. SPECIFIC GRAVITY: 2.5-2.7

vii. CRYSTAL SYSTEM: Hexagonal

viii. DISTINGUISHING CHARACTERISTICS: Conchoidal fracture, glassy luster

ix. CHEMICAL CLASSIFICATION: Silicate

x. CHEMICAL FORMULA: Silicon Dioxide (SiO2)

CHEMICAL PROPERTIES

Clear Quartz is pure, or nearly pure Silicon Dioxide (SiO2), made of Silicon and Oxygen, the Earth’s most common elements. Any impurities are generally trace elements of Aluminum, Lithium, Potassium or Sodium. Quartz has also been found in meteorites and moon rooks.

USES

i. GLASS MANUFACTURING: Occasionally deposited sands that are composed of almost 100% quartz grains. These sands are used in the glassmaking industry. Quartz sand is used in the production of container glass, flat plate glass, specialty glass and fiberglass.

ii. QUARTZ AS ABRASIVE: Quartz sands and finely ground silica sand are used for sand blasting, scouring cleansers, grinding media, and grit for sanding and sawing.

iii. FOUNDARY SAND: Quartz is very resistant to both chemicals and heat. It is therefore often used as a foundry sand. With a melting temperature higher than most metals it can be used for the molds and cores of common foundry work. Quartz sand is also used as a flux in the smelting of metals.

iv. PETROLEUM INDUSTRY: Quartz sand has a high resistance to being crushed. In the petroleum industry sandy slurries are forced down oil and gas wells under very high pressures. This high pressure fractures the reservoir rocks and the sandy slurry injects into the fractures. The durable sand grains hold the fractures open after the pressure is released. These open fractures facilitate the flow of natural gas into the well bore.

v. QUARTZ SAND: Quartz sand is used as filler in the manufacture of rubber, paint and putty. Screened and washed, carefully sized quartz grains are used as filter media and roofing granules. Quartz sands are used for traction in the railroad and mining industries. These sands are also used in recreation on golf courses, volleyball courts, baseball fields, children's sand boxes and beaches.

vi. QUARTZ CRYSTAL: High quality quartz crystals are single-crystal silica with optical or electronic properties that make them useful for specialty purposes. Electronics grade crystals can be used in filters, frequency controls, timers, electronic circuits that become important components in cell phones, watches, clocks, games, television receivers, computers, navigational instruments and other products. Optical-grade crystals can be used as lenses and windows in lasers and other specialized devices.