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  2. Mohs scale - Wikipedia

    en.wikipedia.org/wiki/Mohs_scale

    Hardness may be difficult to determine, or may be misleading or meaningless, if a material is a mixture of two or more substances; for example, some sources have assigned a Mohs hardness of 6 or 7 to granite but it is a rock made of several minerals, each with its own Mohs hardness (e.g. topaz-rich granite contains: topaz — Mohs 8, quartz ...

  3. Hardnesses of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Hardnesses_of_the_elements...

    Toggle the table of contents. Hardnesses of the elements (data page) 10 languages. ... Mohs hardness of materials (data page) Vickers hardness test; Brinell scale

  4. List of mineral tests - Wikipedia

    en.wikipedia.org/wiki/List_of_mineral_tests

    The Mohs Hardness Scale is the main scale to measure mineral hardness. Finger nail is 2.5, copper coin is 3.5, glass is 5.5 and steel is 6.5. Hardness scale is Talc is 1, Gypsum is 2, Calcite is 3, Fluorite is 4, Apatite is 5, Orthoclase Feldspar is 6, Quartz is 7, Topaz is 8, Corundum is 9 and Diamond is 10. Odor; Not always recommended.

  5. Topaz - Wikipedia

    en.wikipedia.org/wiki/Topaz

    Topaz is a silicate mineral made of aluminum and fluorine with the chemical formula Al 2 Si O 4 (F, OH) 2.It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow-orange. [7]

  6. Citrine (quartz) - Wikipedia

    en.wikipedia.org/wiki/Citrine_(quartz)

    Cut yellow topaz, which resembles citrine in color It is nearly impossible to differentiate between cut citrine and yellow topaz visually, but they differ in hardness. All quartz varieties have a hardness of 7 on the Mohs scale , while topaz has a hardness of 8.

  7. Hardness scales - Wikipedia

    en.wikipedia.org/wiki/Hardness_scales

    Scratch hardness. The Mohs scale of mineral hardness; The Vickers hardness test; The Brinell scale; The Janka hardness test; The Rockwell scale; The Durometer scale; The Barcol scale; The Leeb rebound hardness scale; The Rosiwal scale; The Meyer hardness test; The Knoop hardness test

  8. Chrysoberyl - Wikipedia

    en.wikipedia.org/wiki/Chrysoberyl

    Chrysoberyl is the third-hardest frequently encountered natural gemstone and lies at 8.5 on the Mohs scale of mineral hardness, between corundum (9) and topaz (8). [7] An interesting feature of its crystals are the cyclic twins called trillings.

  9. Hardness comparison - Wikipedia

    en.wikipedia.org/wiki/Hardness_comparison

    A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels.