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  2. Mohs scale - Wikipedia

    en.wikipedia.org/wiki/Mohs_scale

    Diamond was the hardest known naturally occurring mineral when the scale was designed, and defines the top of the scale, arbitrarily set at 10. The hardness of a material is measured against the scale by finding the hardest material that the given material can scratch, or the softest material that can scratch the given material.

  3. 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 ...

  4. Gypsum - Wikipedia

    en.wikipedia.org/wiki/Gypsum

    Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4 ·2H 2 O. [4] It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk.

  5. List of minerals - Wikipedia

    en.wikipedia.org/wiki/List_of_minerals

    This is a list of minerals which have Wikipedia articles. Minerals are distinguished by various chemical and physical properties. ... Earth sciences portal;

  6. Diatomaceous earth - Wikipedia

    en.wikipedia.org/wiki/Diatomaceous_earth

    Diatomite rock sample from Sisquoc Formation Scanning electron micrograph of diatomaceous earth. Diatomaceous earth (/ ˌ d aɪ. ə t ə ˈ m eɪ ʃ ə s / DY-ə-tə-MAY-shəs), also known as diatomite (/ d aɪ ˈ æ t ə m aɪ t / dy-AT-ə-myte), celite, or kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder.

  7. Talc - Wikipedia

    en.wikipedia.org/wiki/Talc

    Talc, or talcum, is a clay mineral composed of hydrated magnesium silicate, with the chemical formula Mg 3 Si 4 O 10 (OH) 2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant. It is an ingredient in ceramics, paints, and roofing material.

  8. Soapstone - Wikipedia

    en.wikipedia.org/wiki/Soapstone

    Soapstone is relatively soft because of its high talc content—talc has a definitional value of 1 on the Mohs hardness scale. Softer grades may feel similar to soap when touched, hence the name. No fixed hardness is given for soapstone because the amount of talc it contains varies widely, from as little as 30% for architectural grades such as ...

  9. Earth's mantle - Wikipedia

    en.wikipedia.org/wiki/Earth's_mantle

    Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 10 24 kg (8.84 × 10 24 lb) and makes up 67% of the mass of Earth. [ 1 ] It has a thickness of 2,900 kilometers (1,800 mi) [ 1 ] making up about 46% of Earth's radius and 84% of Earth's volume.