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Related to hornblende: tremolite, augite, biotite


see amphiboleamphibole
, any of a group of widely distributed rock-forming minerals, magnesium-iron silicates, often with traces of calcium, aluminum, sodium, titanium, and other elements.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(1) The most common rock-forming mineral of the group of monoclinic amphiboles (common hornblende). Its approximate chemical composition is Ca2Na[Mg, Fe]4[Al,-Fe][(Si, Al)4O11]2[OH, F]2, with substantial variations in the ratios of basic components and with various element impurities (Na <- K, Ba, Rb; Ca ← TR, Y, Sr, U, W, Mo; Al ← Ga; Mg ← Li; Fe ← Zn, Sc). Hornblende crystallizes in the monoclinic system. It forms long, prismatic needles, irregular grains, and fibrous aggregates of green, black, or brown color. It has a hardness of 5.5–6 on Mohs’ scale and a density of 3,100–3,300 kg/m3. Hornblende is characterized by two directions of well-developed cleavages intersecting at an angle of 124°.

Common hornblende is characteristic of intrusive rocks (granodiorites, syenites, diorites, hornblende gabbros), effusive rocks (andesites, basalts, porphyrites), and metamorphic (am-phibolites, hornblende gneisses) rocks. Common hornblende is a relatively stable mineral, but when acted upon by hydrothermal solutions it alters to chlorite, epidote, calcite, and quartz. In the process of weathering, it decomposes to form opal, carbonates, and various other minerals.

(2) The subgroup of calcium aluminiferous amphiboles that includes common hornblende, edenite, oligoclase, pargasite, and hastingsite.


Deer, W. A., R. A. Howie, and J. Zussmann. Porodoobrazuiushchie mineraly, vol 2. Moscow, 1965. (Translated from English.)
Lodochnikov, V. N. Glavneishie porodoobrazuiushchie mineraly, 5th ed. Moscow, 1974.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A general name given to the monoclinic calcium amphiboles that form an extensive solid-solution series between the various metals in the generalized formula (Ca,Na)2(Mg,Fe,Al)5(Al,Si)8O22(OH,F)2.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


a black or greenish-black mineral of the amphibole group, found in igneous and metamorphic rocks. Composition: calcium magnesium iron sodium aluminium aluminosilicate. General formula: (Ca,Na)2.3(Mg,Fe,Al)5Si6(Si,Al)2O22(OH)2
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Minor constituent 307 Smectite + vermiculite 259 Albite + microcline 263 Muscovite + illite + kaolinite 261 279 Albite + microcline + muscovite + illite 291 S1 Muscovite + illite S3 Hornblende (riebeckite) S4 Chlorite + muscovite + illite S9 S11 Albite + microcline S12 Muscovite + illite + kaolinite S13 255 Muscovite + illite + kaolinite 267 Muscovite + illite + kaolinite 273 288 303 Muscovite + illite S/No.
The presence of euhedral zircon and hornblende (Plates 2 to 6) indicate that ash falls have contributed to this sandstone.
ECM fungi mobilize nutrients from minerals by dissolution of soil mineral particles and most of the inorganic ions taken up by ECM fungi (P[O.sub.4.sup.3-], [Ca.sup.2+], [Mg.sup.2+], [Fe.sup.3+], [K.sup.+]) came from the dissolution of soil mineral particles, such as apatite, feldspars, micas and hornblendes (Landeweert et al.
(15) Schist is formed at high temperatures and high pressures by dynamic metamorphism that aligns the grains of mica, hornblende and other flat or elongated minerals into thin layers, or foliation.
This rock unit is characterised by grey foliated Biotite acid/Biotite Hornblende quartz feldspathic gneiss of tonalitic to granodioritic composition [12];Mafic to ultramafic component which outcrops as discontinuous boudinaged lenses or concordant sheet of amplibolites with minor amount of biotite-rich ultramafite; and Felsic component, a varied group comprised of pegmatite, aplite quartz-oligoclase veins, fine-grained granite gneiss, and porphyritic granite.
A hornblende diorite, weakly to moderately magnetic, has intruded the andesite / limestone sequence.
Hornblende is found in some of the summit samples, as are small gabbroic, plagioclase-magnetite, and ultramafic xenoliths that may represent disaggregated cumulates (Herzer 1971).
(Actually this is likely to have been known by Stone Age Man too, but I don't have their names and addresses.) If it helps - it didn't help me - the most musical rocks are Gneiss and Hornblende Schist.