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2. Chert - Wikipedia

   en.wikipedia.org/wiki/Chert

   Chert varies greatly in color, from white to black, but is most often found as gray, brown, grayish brown and light green to rusty red [9] [10] and occasionally as dark green. [11] Its color is an expression of trace elements present in the rock. Both red and green are most often related to traces of iron in its oxidized and reduced forms ...

3. Quartz - Wikipedia

   en.wikipedia.org/wiki/Quartz

   Quartz. Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO 4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO 2. Quartz is, therefore, classified structurally as a framework silicate mineral ...

4. Quartzite - Wikipedia

   en.wikipedia.org/wiki/Quartzite

   Quartzite. Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone. [1][2] Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and ...

5. Chalcedony - Wikipedia

   en.wikipedia.org/wiki/Chalcedony

   Chalcedony. Chalcedony (/ kælˈsɛdəni / kal-SED-ə-nee, or / ˈkælsəˌdoʊni / KAL-sə-doh-nee) [2] is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. [3] These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic.

6. Chlorite group - Wikipedia

   en.wikipedia.org/wiki/Chlorite_group

   The chlorites are the group of phyllosilicate minerals common in low-grade metamorphic rocks and in altered igneous rocks. Greenschist, formed by metamorphism of basalt or other low-silica volcanic rock, typically contains significant amounts of chlorite. Chlorite minerals show a wide variety of compositions, in which magnesium, iron, aluminium ...

7. Granite - Wikipedia

   en.wikipedia.org/wiki/Granite

   Granite. Granite (/ ˈɡrænɪt / GRAN-it) is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground.

8. AOL Mail

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   Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!

9. Jasper - Wikipedia

   en.wikipedia.org/wiki/Jasper

   Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, [1][2] is an opaque, [3] impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron (III) inclusions. Jasper breaks with a smooth surface and is used for ornamentation or as ...