Geochemistry.quartz.environment of earthpptx

quartz

1. Quartz

2. Contents: ● Etymology and history of quartz ● Mineral Groups of quartz ● Chemical Composition of quartz ● Crystal system of quartz ● Physical properties ● Occurrence ● Uses ● References       2

3. Etymology and history The word "quartz" is derived from the German word " Quarz ", which had the same form in the first half of the 14th century in Middle High German and in East Central Germanand which came from the Polish dialect term kwardy . Quartz mineral consisting of silicon dioxide occurring in colorless and transparent or colored hexagonal crystals or in crystalline masses. 3

4. Mineral Groups of Quartz Quartz is one of the most common minerals in the Earth’s crust. As a mineral name, quartz refers to a specific chemical compound (silicon dioxide, or silica, SiO2), having a specific crystalline form (hexagonal). It is found in all forms of rock: igneous, metamorphic and sedimentary. Quartz is physically and chemically resistant to weathering. When quartz-bearing rocks become weathered and eroded, the grains of resistant quartz are concentrated in the soil, in rivers, and on beaches. The white sands typically found in river beds and on beaches are usually composed mainly of quartz, with some white or pink feldspar as well. 4

5. Chemical composition Quartz is our most common mineral. Quartz is made of the two most abundant chemical elements on Earth: oxygen and silicon. Atoms of oxygen and silicon join together as tetrahedrons (three sided pyramids).These stack together to build crystals. Billions of tetrahedrons are needed to build even a small crystal. Quartz is an almost pure chemical compound with constant physical properties. Quartz makes up about 12 percent of the land surface and about 20 percent of the Earth's crust. Most of the remaining crustal rocks are rich in silicate minerals which include silicon and oxygen together with other elements. 5

6. Physical properties   Chemical classification Silicate Color Quartz occurs in virtually every color. Common colors are clear, white, gray, Purple , black, pink, green, red, Yellow . Streak Colorless (harder than the streak plate) Luster Vitreous Mohs Hardness 7 Specific Gravity 2.6 to 2.7 Chemical Composition SiO2 Crystal System Hexagonal 6

7. Occurrences: Quartz occurs as an important constituent of those igneous rocks which have an excess of silica, such as granite, rhyolite, pegmatite. It is extremely resistant to both mechanical and chemical attack, and thus the breakdown of igneous rocks containing it yields quartz grains which may accumulate and form the sedimentary rock sandstone. Also occurs in metamorphic rocks, as gneisses and schists , while it forms practically the only mineral of quartzites . 7

8. Crystal system Quartz belongs to the trigonal crystal system at room temperature, and to the hexagonal crystal system above 573 °C (846 K; 1,063 °F). The ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end. 8

9. Uses Geological processes have occasionally deposited sands which are composed of virtually one hundred% quartz grains. Quartz sand is used inside the production of field glass, flat plate glass,uniqueness glass, and fiberglass. The high hardness of quartz, seven at the Mohs Scale, makes it more difficult than most different natural materials. Quartz sands and finely floor silica sand are used for sand blasting, scouring cleansers, grinding media,and grit for sanding and sawing. It may be very proof against both chemical compounds and heat. Quartz sand is likewise used as a flux in the smelting of metals. Quartz sand has a excessive resistance to being beaten. These open fractures facilitate the flow of natural gas into the properly bore. Quartz sand is used as a filler inside the manufacture of rubber, paint, and putty. These sands also are used in recreation on golfing publications, volleyball courts, baseball fields, kid’s sand boxes and seashores. It makes an terrific gemstone. 9

10. 10 • Bonewitz , R. (2012). Rocks and minerals. 2nd ed. London: DK Publishing. • Dana, J. D. (1864). Manual of Mineralogy… Wiley. • Handbook of Mineralogy. [online] Available at: http://www.handbookofmineralogy.org [Accessed 19 Mar. 2023]. • Mineral information, data and localities.. [online] Available at: https://www.mindat.org/ [Accessed 19 Mar. 2023]. • Smith College. [online] Available at: https://www.smith.edu/academics/geosciences [Accessed 19 Mar. 2023]. References

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