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  2. Pyrite - Wikipedia

    en.wikipedia.org/wiki/Pyrite

    Pyrite cubic crystals on marl from Navajún, La Rioja, Spain (size: 95 by 78 millimetres [3.7 by 3.1 in], 512 grams [18.1 oz]; main crystal: 31 millimetres [1.2 in] on edge) Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold.

  3. Euhedral and anhedral - Wikipedia

    en.wikipedia.org/wiki/Euhedral_and_anhedral

    Euhedral pyrite crystals A subhedral sample showing sharp to anhedral pyrargyrite crystals. Euhedral and anhedral are terms used to describe opposite properties in the formation of crystals . Euhedral (also known as idiomorphic or automorphic ) crystals are those that are well-formed, with sharp, easily recognised faces .

  4. Cubic crystal system - Wikipedia

    en.wikipedia.org/wiki/Cubic_crystal_system

    In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There are three main varieties of these crystals: Primitive cubic (abbreviated cP and alternatively called simple cubic)

  5. Pyrite group - Wikipedia

    en.wikipedia.org/wiki/Pyrite_group

    The group is named for its most common member, pyrite (fool's gold), which is sometimes explicitly distinguished from the group's other members as iron pyrite. Pyrrhotite (magnetic pyrite) is magnetic, and is composed of iron and sulfur , but it has a different structure and is not in the pyrite group.

  6. Nodule (geology) - Wikipedia

    en.wikipedia.org/wiki/Nodule_(geology)

    Devonian nodular limestone Concretionary nodular limestone at Jinshitan Coastal National Geopark, Dalian, China. In geology and particularly in sedimentology, a nodule is a small, irregularly rounded knot, mass, or lump of a mineral or mineral aggregate that typically has a contrasting composition from the enclosing sediment or sedimentary rock.

  7. Dodecahedron - Wikipedia

    en.wikipedia.org/wiki/Dodecahedron

    In pyritohedral pyrite, the faces have a Miller index of (210), which means that the dihedral angle is 2·arctan(2) ≈ 126.87° and each pentagonal face has one angle of approximately 121.6° in between two angles of approximately 106.6° and opposite two angles of approximately 102.6°. The following formulas show the measurements for the ...

  8. List of minerals - Wikipedia

    en.wikipedia.org/wiki/List_of_minerals

    Amethyst crystals – a purple quartz Apophyllite crystals sitting right beside a cluster of peachy bowtie stilbite Aquamarine variety of beryl with tourmaline on orthoclase Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals Austinite from the Ojuela Mine, Mapimí, Durango, Mexico Ametrine ...

  9. File:Rhodonite, pyrite, quartz 1.jpg - Wikipedia

    en.wikipedia.org/wiki/File:Rhodonite,_pyrite...

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