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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. 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 ...

  4. 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.

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

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

    Print/export Download as PDF; Printable version; In other projects Wikidata item; Appearance. ... Mohs scale of mineral hardness; Mohs hardness of materials (data page)

  6. Emerald - Wikipedia

    en.wikipedia.org/wiki/Emerald

    Emerald is a gemstone and a variety of the mineral beryl (Be 3 Al 2 (SiO 3) 6) colored green by trace amounts of chromium or sometimes vanadium. [2] Beryl has a hardness of 7.5–8 on the Mohs scale. [2] Most emeralds have many inclusions, [3] so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate.

  7. 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.

  8. 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]

  9. Taaffeite - Wikipedia

    en.wikipedia.org/wiki/Taaffeite

    Taaffeite (/ ˈ t ɑː f aɪ t /; BeMgAl 4 O 8) is a mineral, named after its discoverer Richard Taaffe (1898–1967) who found the first sample, a cut and polished gem, in October 1945 in a jeweler's shop in Dublin, Ireland. [4] [5] As such, it is the only gemstone to have