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2. 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 ...

3. Amethyst - Wikipedia

   en.wikipedia.org/wiki/Amethyst

   Amethyst is a purple variety of quartz (SiO. 2) and owes its violet color to irradiation, impurities of iron (Fe3+. ) and in some cases other transition metals, and the presence of other trace elements, which result in complex crystal lattice substitutions. [2][3][4] The irradiation causes the iron Fe3+.

4. Geode - Wikipedia

   en.wikipedia.org/wiki/Geode

   Geode. A geode (/ ˈdʒiː.oʊd /; from Ancient Greek γεώδης (geṓdēs) 'earthlike') is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the filling of vesicles in ...

5. Durr Al Najaf - Wikipedia

   en.wikipedia.org/wiki/Durr_Al_Najaf

   Durr Al Najaf (Arabic: دُر ٱلنَّجَف) is a glossy and clear gemstone from the quartz family. The name means "pearl of Najaf " as it can only be sourced from Wadi-al-Salaam (Arabic: وادي السلام, romanized: Wādī al-Salām, lit. 'Valley of Peace') in Najaf, Iraq. The gemstone is found along the west of Najaf close by the ...

6. Quartz Vs. Granite: Which Stone Is Right For Your ... - AOL

   www.aol.com/quartz-vs-granite-stone-countertops...

   Whereas quartz countertops are man-made, granite is a naturally occurring stone, quarried from the earth, then cut and polished into the countertop material so many know and love. Made of stern ...

7. Crystal - Wikipedia

   en.wikipedia.org/wiki/Crystal

   Crystal. Crystals of amethyst quartz. Microscopically, a single crystal has atoms in a near-perfect periodic arrangement; a polycrystal is composed of many microscopic crystals (called "crystallites" or "grains"); and an amorphous solid (such as glass) has no periodic arrangement even microscopically. A crystal or crystalline solid is a solid ...