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  2. List of mineral tests - Wikipedia

    en.wikipedia.org/wiki/List_of_mineral_tests

    Mineral tests are simple physical and chemical methods of testing samples, which can help to identify the mineral type. [1] This approach is used widely in mineralogy, ore geology and general geological mapping. [2]

  3. Conoscopic interference pattern - Wikipedia

    en.wikipedia.org/wiki/Conoscopic_interference...

    A conoscopic interference pattern or interference figure is a pattern of birefringent colours crossed by dark bands (or isogyres), which can be produced using a geological petrographic microscope for the purposes of mineral identification and investigation of mineral optical and chemical properties.

  4. Amethyst - Wikipedia

    en.wikipedia.org/wiki/Amethyst

    As amethyst is readily available in large structures, the value of the gem is not primarily defined by carat weight. This is different from most gemstones, since the carat weight typically exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed. [41]

  5. Glass coloring and color marking - Wikipedia

    en.wikipedia.org/wiki/Glass_coloring_and_color...

    In borosilicate glasses rich in boron, sulfur imparts a blue color. With calcium it yields a deep yellow color. [4] Manganese can be added in small amounts to remove the green tint given by iron, or in higher concentrations to give glass an amethyst color. Manganese is one of the oldest glass additives, and purple manganese glass was used since ...

  6. Ametrine - Wikipedia

    en.wikipedia.org/wiki/Ametrine

    Ametrine, also known as trystine, golden amethyst, or by the trade name bolivianite, is a variety of quartz with alternating zones of purple and yellow-orange coloration. Its name is a portmanteau of amethyst and citrine. While ametrine is commonly referred to as a combination of these two quartz varieties, some sources claim this is not ...

  7. Amethyst (color) - Wikipedia

    en.wikipedia.org/?title=Amethyst_(color)&redirect=no

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  9. Prasiolite - Wikipedia

    en.wikipedia.org/wiki/Prasiolite

    Prasiolite (also known as green quartz, green amethyst or vermarine) is a green variety of quartz. Since 1950, almost all natural prasiolite has come from a small Brazilian mine, [ citation needed ] but it has also been mined in the Lower Silesia region of Poland .