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  2. Inclusion (mineral) - Wikipedia

    en.wikipedia.org/wiki/Inclusion_(mineral)

    In mineralogy, an inclusion is any material trapped inside a mineral during its formation. In gemology , it is an object enclosed within a gemstone or reaching its surface from the interior. [ 1 ] According to James Hutton 's law of inclusions, fragments included in a host rock are older than the host rock itself.

  3. Color index (geology) - Wikipedia

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

    Speaking broadly, mineral color points out the specific gravity of the mineral, as minerals that are lighter in color tend to be less dense. Darker minerals typically tend to contain more of relatively heavy elements, notably iron, magnesium, and calcium. [2] The temperature of crystallization affects what the color index of rocks tends to be. [10]

  4. Jet (gemstone) - Wikipedia

    en.wikipedia.org/wiki/Jet_(gemstone)

    Jet is a type of lignite, [1] the lowest rank of coal, and is a gemstone.Unlike many gemstones, jet is not a mineral, but is rather a mineraloid. [2] It is derived from wood that has changed under extreme pressure.

  5. List of U.S. state minerals, rocks, stones and gemstones

    en.wikipedia.org/wiki/List_of_U.S._state...

    In 1986, California named benitoite as its state gemstone, a form of the mineral barium titanium silicate that is unique to the Golden State and only found in gem quality in San Benito County. [ 80 ] ^ Colorado is the only state whose geological symbols reflect the national flag's colors: red (rhodochrosite), white (yule marble), and blue ...

  6. Diamond inclusions - Wikipedia

    en.wikipedia.org/wiki/Diamond_inclusions

    The timing of mineral crystallization can be used to categorize diamond inclusions into three types: protogenetic, syngenetic, and epigenetic inclusions. [14] Minerals in the protogenetic inclusions were crystallized earlier than the diamond formation. The host diamond encapsulated pre-existing minerals during its crystallization.

  7. Allende meteorite - Wikipedia

    en.wikipedia.org/wiki/Allende_meteorite

    When an Allende stone is sawed into two pieces and the surface is polished, the structure in the interior can be examined. This reveals a dark matrix embedded throughout with mm-sized, lighter-colored chondrules, tiny stony spherules found only in meteorites and not in earth rock (thus it is a chondritic meteorite). Also seen are white ...

  8. Mafic - Wikipedia

    en.wikipedia.org/wiki/Mafic

    A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase ...

  9. List of minerals recognized by the International ...

    en.wikipedia.org/wiki/List_of_minerals_recognized...

    This list includes those recognised minerals beginning with the letters U and V.The International Mineralogical Association is the international group that recognises new minerals and new mineral names; however, minerals discovered before 1959 did not go through the official naming procedure, although some minerals published previously have been either confirmed or discredited since that date.