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2. Quartz - Wikipedia

   en.wikipedia.org/wiki/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 and ...

3. Pegmatite - Wikipedia

   en.wikipedia.org/wiki/Pegmatite

   Pegmatite. A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite.

4. Gemstone - Wikipedia

   en.wikipedia.org/wiki/Gemstone

   Gemstone. Group of precious and semiprecious stones—both uncut and faceted—including (clockwise from top left) diamond, uncut synthetic sapphire, ruby, uncut emerald, and amethyst crystal cluster. A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or ...

5. Desert rose (crystal) - Wikipedia

   en.wikipedia.org/wiki/Desert_rose_(crystal)

   A desert rose is an intricate rose -like formation of crystal clusters of gypsum or baryte, which include abundant sand grains. [1] The "petals" are crystals flattened on the c axis, fanning open in radiating clusters. The rosette crystal habit tends to occur when the crystals form in arid sandy conditions, [1] such as the evaporation of a ...

6. Lepidolite - Wikipedia

   en.wikipedia.org/wiki/Lepidolite

   Lepidolite. Pink, light purple, purple, rose-red, violet-gray, yellowish, white, colorless other colors possible but are rare. Lepidolite is a lilac -gray or rose-colored member of the mica group of minerals with chemical formula K (Li,Al)3(Al,Si,Rb)4O10(F,OH)2. [2][3] It is the most abundant lithium -bearing mineral [4] and is a secondary ...

7. 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+.