Biotite - Wikipedia
Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate stone formula K(Mg,Fe) 3AlSi 3O 10(F,OH) 2. It is primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous end-members include siderophyllite and eastonite.
Biotite Mineral Data
General Biotite Information : stone Formula: K(Mg,Fe++)3[AlSi3O10(OH,F)2 : Composition: Molecular Weight = 433.53 gm Potassium 9.02 % K 10.86 % K 2 O Magnesium 14.02 % Mg 23.24 % MgO Aluminum 6.22 % Al 11.76 % Al 2 O 3 Iron 6.44 % Fe 8.29 % FeO Silicon 19.44 % Si 41.58 % SiO 2
Biotite Mica Mineral | Physical and Optical …
22.04.2018 · Biotite is the most common mica mineral and also known as black mica, a silicate mineral in the common mica group. Approximate stone formula K (Mg, Fe). It can be found in massive crystal layers weighing several hundred pounds. It is abundant in metamorphic rocks (both regional and contact),
Biotite Mineral | Uses and Properties
A generalized stone composition for the biotite group is: K(Mg,Fe) 3 (AlSi 3 O 10)(F,OH) 2. The name "biotite" is used in the field and in entry-level geology courses because these minerals generally cannot be distinguished without optical, chemical, or x-ray analysis.
Biotite composition as a tool for the identification …
In addition, devitrified lavas that are unsuitable for glass analysis can be correlated to coeval tephra deposits by their biotite compositions. Biotite is common in high-K 2 O (>4 wt%) tephra beds and is widely dispersed in ash plumes because of its platy form, thus making it …
(PDF) stone composition of biotite as a guide …
Biotite, the dominant ferromagnesian mineral in granitoid rocks, can be used to discriminate tectonic setting, magma types and magnetite-ilmenite series. …
Using magmatic biotite chemistry to differentiate …
23.06.2020 · The Fe2+/(Fe2+ + Mg2+) ratio of biotite varies as a function of intrusion metal affinity, increasing from Cu–Mo-related (mean of 0.56 ± 0.12), to Mo-related (mean of 0.69 ± 0.06) to Sn–W-related (mean of 0.77 ± 0.16), with barren granitoids lying …
Biotite — Wikipédia
La biotite est un minéral, du groupe des silicates, sous-groupe des phyllosilicates de la famille des micas. Elle forme une série avec le phlogopite . De formule idéale K(Mg,Fe) 3 (OH,F) 2 (Si 3 AlO 10 ) avec des traces de : Mn;Ti;Li;Ba;Na;Sr;Cs;Fe;Cl.
Analysis of the compositional variations of biotite in ...
Biotite and its components The composition of a chemically complex mineral like biotite can be expressed in many ways. A first method is to consider the composition as a point in n-dimensional space in which the coordinate axes are the number of cations per 12 (O,OH).
Biotite - science.smith.edu
Biotite: Property: Value: Comments: Formula: K(Mg,Fe) 3 AlSi 3 O 10 (OH,O,F) 2: Shows substantial variability in composition that can be represented with the four end members: Annite= KFe 3 AlSi 3 O 10 (OH) 2. Phlogopite= KMg 3 AlSi 3 O 10 (OH) 2. Siderophyllite KFe 2 AL(Al 2 Si 2 O 10)(OH) 2. Unnamed end member (formerly known as eastonite)= KMg 2 Al(Al 2 Si 2 O 10)(OH) 2. The variation in ...
(PDF) Composition of biotite phenocrysts in …
Biotite phenocryst compositions in three thick, widespread Ordovician K-bentonites, the Deicke and Millbrig from Big Ridge, Alabama, and the Kinnekulle from Mossen, V¨asterg¨otland, Sweden, fall...
Fluorine-controlled composition of biotite in …
23.08.2019 · Because of the strong preference of fluorine (F) for “hydrous” magnesian silicate minerals, the temperature T (0F) given by the reaction (Bi–Gt) of Fe–Mg exchange between biotite and garnet [phlogopite (Phl) + almandine (Alm) = annite (Ann) + pyrope (Py)] can be dramatically underestimated when the reciprocal effects between octahedral and hydroxyl site occupancies in biotite are ignored.
Primary magmatic biotite in granitoid intrusions ...
All primary magmatic biotite grains are Mg-rich in composition (X Mg = Mg/(Mg + Fe) = 0.41–0.69). The Cl contents of biotite (0.09–0.42 wt%) in the Loushang quartz diorite and the Duimiangou massive granodiorite correlate negatively with X Mg and are consistent with the “Mg-Cl avoidance” rule.
Granite - Wikipedia
Potassium feldspar, plagioclase feldspar, and quartz; differing amounts of muscovite, biotite, and hornblende -type amphiboles Granite (/ ˈɡrænɪt /) is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy.
Biotite - GEO143 Mineral Webpages
Mineral Group: Biotite is very common within the Mica group. It also belongs to the silicate group and the phyllosilicates group. Biotite is included in the silicates group because the composition...
University of Minnesota’s Mineral Pages: Biotite
Biotite is commonly associated with muscovite, quartz, feldspars, and amphibole minerals in igneous rocks, while phlogopite is more often found with olivine and pyroxene.
ALTERATION OF MUSCOVITE AND BIOTITE IN THE SOIL
In order to study the changes in stone composition that musco- vite and biotite undergo in the soil, samples of mica were isolated from many soil horizons. These samples of practically pure mica were analyzed, the proportions of muscovite and biotite determined petro- graphically, and the compositions of the samples compared with those of fresh muscovite and biotite. The rates at which the ...