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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. 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 ...

  4. Tourmaline - Wikipedia

    en.wikipedia.org/wiki/Tourmaline

    Rarely, it can be found as neon green or electric blue. Tourmaline (/ ˈtʊərməlɪn, - ˌliːn / TOOR-mə-lin, -⁠leen) is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a wide variety of colors.

  5. Aventurine - Wikipedia

    en.wikipedia.org/wiki/Aventurine

    Aventurine. Aventurine is used for a number of applications, including landscape stone, building stone, aquaria, monuments, and jewelry. Aventurine is a form of quartzite, characterised by its translucency and the presence of platy mineral inclusions that give it a shimmering or glistening effect termed aventurescence.

  6. Amethyst - Wikipedia

    en.wikipedia.org/wiki/Amethyst

    Other names for green quartz are vermarine and lime citrine. Amethyst frequently shows color zoning, with the most intense color typically found at the crystal terminations. One of gem cutters' tasks is to make a finished product with even color. Sometimes, only a thin layer of a natural, uncut amethyst is violet colored, or the color is very ...

  7. Granite - Wikipedia

    en.wikipedia.org/wiki/Granite

    Granite is a natural source of radiation, like most natural stones. Potassium-40 is a radioactive isotope of weak emission, and a constituent of alkali feldspar, which in turn is a common component of granitic rocks, more abundant in alkali feldspar granite and syenites. Some granites contain around 10 to 20 parts per million (ppm) of uranium.

  8. Tanzanite - Wikipedia

    en.wikipedia.org/wiki/Tanzanite

    Present, dichroism or trichroism, depending on heat treatment. Tanzanite is the blue and violet variety of the mineral zoisite (a calcium aluminium hydroxyl sorosilicate), caused by small amounts of vanadium. [3] Tanzanite belongs to the epidote mineral group. Tanzanite is only found in Simanjiro District of Manyara Region in Tanzania, in a ...

  9. Mineralogy of the Pikes Peak Region - Wikipedia

    en.wikipedia.org/wiki/Mineralogy_of_the_Pikes...

    For example, amazonite can be found next to Barr Trail, the main hiking route to the summit of Pikes Peak. The most famous collecting area on the Peak is Glenn Cove, a glacial cirque located at 11,000 feet (3,400 m) on the north side of the mountain. Quartz crystals, amazonite and topaz crystals can be found in pockets on steep cliffs in this area.