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2. Rhodochrosite - Wikipedia

   en.wikipedia.org/wiki/Rhodochrosite

   Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO 3. In its pure form (rare), it is typically a rose-red colour, [5] but it can also be shades of pink to pale brown. It streaks white, [6] and its Mohs hardness varies between 3.5 and 4.5. Its specific gravity is between 3.45 and 3.6. [7]

3. 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 ...

4. Selenite (mineral) - Wikipedia

   en.wikipedia.org/wiki/Selenite_(mineral)

   Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum.. All varieties of gypsum, including selenite and alabaster, are composed of calcium sulfate dihydrate (meaning that it has two molecules of water), with the chemical formula CaSO 4 ·2H 2 O. Selenite contains no significant selenium – The similar names both derive from Greek selḗnē ...

5. 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 ...

6. 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 ...

7. 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.

8. List of U.S. state minerals, rocks, stones and gemstones

   en.wikipedia.org/wiki/List_of_U.S._state...

   Rose quartz (1966) Fairburn agate (1966) and State Jewelry: Black Hills Gold: Tennessee [66] Agate (2009) Limestone (from 1979 to present) and formerly.

9. Heliotrope (mineral) - Wikipedia

   en.wikipedia.org/wiki/Heliotrope_(mineral)

   The mineral aggregate heliotrope (from Ancient Greek ἥλιος (hḗlios) 'sun' and τρέπειν (trépein) 'to turn'), also called Indian bloodstone or ematille, is a cryptocrystalline mixture of quartz that occurs mostly as jasper (opaque) or sometimes as chalcedony (translucent). The "classic" bloodstone is translucent to opaque green ...