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  2. 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 .

  3. Mohs scale - Wikipedia

    en.wikipedia.org/wiki/Mohs_scale

    Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale The Mohs scale ( / m oʊ z / MOHZ ) of mineral hardness is a qualitative ordinal scale , from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.

  4. Lonsdaleite - Wikipedia

    en.wikipedia.org/wiki/Lonsdaleite

    Its hardness is theoretically superior to that of cubic diamond (up to 58% more), according to computational simulations, but natural specimens exhibited somewhat lower hardness through a large range of values (from 7–8 on Mohs hardness scale). The cause is speculated as being due to the samples having been riddled with lattice defects and ...

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

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

    Mohs scale of mineral hardness; Mohs hardness of materials (data page) Vickers hardness test; Brinell scale This page was last edited on ...

  6. Jadeite - Wikipedia

    en.wikipedia.org/wiki/Jadeite

    Jadeite is a pyroxene mineral with composition Na Al Si 2 O 6.It is hard (Mohs hardness of about 6.5 to 7.0), very tough, and dense, with a specific gravity of about 3.4.It is found in a wide range of colors, but is most often found in shades of green or white.

  7. Chrysocolla - Wikipedia

    en.wikipedia.org/wiki/Chrysocolla

    Chrysocolla exhibits a wide range of Mohs hardness ranging from 2 through 7, which is dependent on the amount of silica incorporated into the stone when it is forming. Generally, dark navy blue chrysocolla is too soft to be used in jewelry, while cyan, green, and blue-green chrysocolla can have a hardness approaching 6, similar to turquoise.

  8. Calcite - Wikipedia

    en.wikipedia.org/wiki/Calcite

    Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO 3).It is a very common mineral, particularly as a component of limestone.Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison.

  9. Diopside - Wikipedia

    en.wikipedia.org/wiki/Diopside

    At 5.5–6.5 on the Mohs scale, chrome diopside is relatively soft to scratch. Due to the deep green color of the gem, they are sometimes referred to as Siberian emeralds, although they are on a gemological level completely unrelated, emerald being a precious stone and diopside being a semi-precious stone. [10]