• WordNet 3.6
    • n biotite dark brown to black mica found in igneous and metamorphic rock
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Webster's Revised Unabridged Dictionary
    • n Biotite (Min) Mica containing iron and magnesia, generally of a black or dark green color; -- a common constituent of crystalline rocks. See Mica.
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Century Dictionary and Cyclopedia
    • n biotite An important member of the mica group of minerals. See mica. It occurs in hexagonal prisms, sometimes tabular, of a black or dark-green color. It is a silicate of aluminium and iron with magnesium and potassium, and is often called magnesia mica, in distinction from muscovite or potash mica. It is sometimes divided into two varieties, called anomite and meroxene, which are distinguished by optical characteristics.
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Webster's Revised Unabridged Dictionary
From Biot, a French naturalist


In literature:

These are the measurements in biotite.
"The Birth-Time of the World and Other Scientific Essays" by J. (John) Joly
Black mica (biotite) is not infrequently to be seen.
"Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 3" by Various
Chlorite arises from biotite, augite and hornblende.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4" by Various
More rarely biotite and augite exhibit the same relations to the plagioclase.
"Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 5" by Various
The dark matrix consists of biotite, aegirine-augite and melanite.
"Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3" by Various
Biotite is, however, readily distinguished by its darker colour, strong pleochroism, and small optic axial angle.
"Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7" by Various
Biotite, if present, is brown; epidote is yellow or colourless; rutile, apatite and quartz all occur with some frequency.
"Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6" by Various
Muscovite and biotite may both occur in the same rock; in other cases only one of them is present.
"Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2" by Various
Often they enclose dark crystals of biotite and hornblende, arranged zonally.
"Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3" by Various
Among other minerals found in them are biotite and chlorite, tourmaline, epidote, apatite, garnet, hornblende and augite, sphene, pyrites.
"Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 5" by Various

In science:

In particular, irradiations of Fe on Biotite (an iron-rich mica variety) and Zr on Zircon ( ZrSiO4 ), would be desirable to determine their possible utility.
Nuclear Tracks from Cold Dark Matter Interactions in Mineral Crystals: A Computational Study