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Topic: Amphibole


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In the News (Thu 24 Jan 19)

  
  Amphibole - Wikipedia, the free encyclopedia
The chief difference between amphiboles and pyroxenes is in cleavage: amphiboles form oblique cleavage planes, while pyroxenes have cleavages of approximately 90 degrees.
Amphiboles are also specifically less dense than the corresponding pyroxenes, and in their optical characteristics they are distinguished by their stronger pleochroism and by the wider angle of extinction on the plane of symmetry.
Amphiboles are minerals of either original or secondary origin; in the former case occurring as constituents (hornblende) of igneous rocks, such as granite, diorite, andesite and others.
en.wikipedia.org /wiki/Amphibole   (533 words)

  
 [No title]
Amphibole grp., apatite grp., augite, biotite, calcite, chalcopyrite, dolomite, magnetite, olivine, phlogopite, pyrite, pyrochlore, pyrrhotite, riebeckite, salite, titanite, zircon.
Aegirine, amphibole grp., analcime, apatite grp., barite, biotite, calcite, cancrinite, chalcopyrite, chlorite, grp., diopsiide, dolomite, fluorite, garnet grp., hematite, kaersutite, magnetite, muscovite (sericite), nepheline, olivine, perthite, pyrite, pyroxene grp., pyrrhotite.
Aegirine-augite, amphibole grp., apatite grp., barite, betafite, calcite, dolomite, eckermannite, fluorite, galena, magnetite, phlogopite, pyrite, pyroxene grp., pyrrhotite, quartz, richterite, vermiculite, zircon.
www.koeln.netsurf.de /~w.steffens/can.htm   (2311 words)

  
 AMPHIBOLE   (Site not responding. Last check: 2007-10-20)
Amphiboles are usually dark green to fl in colour and usually almost opaque; they show good cleavages which intersect at an angle of about 60 degrees; amphiboles are fairly hard (5-6); amphibole does NOT react with hydrochloric acid.
Amphibole is a very common mineral in intermediate composition igneous rocks such as andesites, and may be the main mineral in greenschist metamorphic rocks.
Amphibole is not economically important as an individual mineral and is not commercially extracted from sedimentary rocks.
www.brookes.ac.uk /geology/sedmins/amphibol.html   (438 words)

  
 [No title]
Aegirine, albite, amphibole grp., analcime, apatite grp., augite, biotite, diopside, feldspar grp., hornblende, leucite, magnetite, melilite, monticellite, natrolite, nepheline, olivine, quartz, sanidine, titanite, zeolite grp..
Aegirine, aegirine-augite, akermanite, amphibole grp., apatite grp., augite, barite, bastnaesite, biotite, calcite, diopside,dolomite, fluorite, ilmenite, magnetite, melanite, melilite, microcline, nepheline, othoclase, parisite, perovskite, pyrite, pyrochlore, siderite, synchysite, titanite, vermiculite.
Amphibole grp., analcime, biotite, hornblende, oligoclase, perthite, pyroxene grp., quartz.
www.koeln.netsurf.de /~w.steffens/usa.htm   (1991 words)

  
 Search Results for Amphibole - Encyclopædia Britannica
Igneous amphiboles are intermediate in composition between tremolite, tschermakite, edenite, and pargasite end-members.
Amphiboles are found principally in metamorphic and igneous rocks.
Amphibole mineral, a magnesium and iron silicate that occurs in...
www.britannica.com /search?query=Amphibole   (282 words)

  
 ATSDR - Asbestos - Tremolite Asbestos   (Site not responding. Last check: 2007-10-20)
The Virginia amphibole (identified as actinolite) and the South African amphibole (identified as anthophyllite) were predominately nonasbestiform, whereas the Montana amphibole (identified as actinolite) was predominately asbestiform (Moatamed et al.
Amphibole (reported as tremolite) was detected in 26 of 57 samples of vermiculite with concentrations ranging from 0.01% to 6.4% in the samples with tremolite (Addison and Davies 1990).
Amphibole asbestos, identified as tremolite asbestos or actinolite asbestos, has been reported to be a minor contaminant in some deposits of chrysotile in Quebec.
www.atsdr.cdc.gov /asbestos/doc_tremolite.html   (14407 words)

  
 Compositional Zoning in Amphibole from Amphibole Bearing Parageneses of West Psunj (Croatia): Evidence for Progressive ...   (Site not responding. Last check: 2007-10-20)
Amphibole bearing parageneses from the western part of Mt. Psunj (Croatia) record evidence of prograding metamorphism.
Changes in the chemical composition of amphibole grains are interpreted through coupled substitutions, and reactions with co-existing minerals during an increase in metamorphic conditions from greenschist to amphibolite facies.
The change in P-T conditions recorded in the growth of amphibole grains (general prograding pattern) together with changes in the modal compositions in related parageneses could be interpreted in a model of a subduction zone.
www.geologia-croatica.hr /abstract/gc-50-1-02.html   (153 words)

  
 HYDROTHERMAL AMPHIBOLE IN SUBGREENSCHIST FACIES METAVOLCANIC ROCKS, NORTHERN SIERRA NEVADA, CALIFORNIA   (Site not responding. Last check: 2007-10-20)
However, the sub-calcic amphiboles are distinct from the actinolite that is commonly reported in the Prh-Pmp facies and we interpret them to have formed during hydrothermal metamorphism associated with the intrusion of the abundant diabases.
The sub-calcic amphiboles are found as veins that cut Cpx phenecrysts, as euhedra in hydrothermal Qtz and Prh, and as needles around amydules in the Pmp-bearing groundmass of volcanic flows that otherwise lack amphibole.
Thus, we infer that the sub-calcic amphibole was formed by hydrothermal interactions during the intrusion of the mafic diabases into the volcanic sequence.
gsa.confex.com /gsa/2001AM/finalprogram/abstract_19365.htm   (434 words)

  
 Amphibole Minerals Case   (Site not responding. Last check: 2007-10-20)
The amphibole group constitutes the most chemically complex mineral group in nature and their component atoms have a distinctive arrangement known as a double silicate chain.
Amphiboles are essential minerals of igneous and metamorphic rocks and are wide spread in New York State with 22 species known to be present.
Our amphibole collection is currently the subject of ongoing research by the Museum's Center for Mineralogy.
www.nysam.org /amphibole   (158 words)

  
 METAMORPHIC PETROLOGY   (Site not responding. Last check: 2007-10-20)
Brown amphibole is common as rims around clinopyroxene that is partly to completely replaced by green amphibole in the center.
Average amphibole vein density at Sites 921 and 923 is 1–10 veins/m of core (Dilek et al., 1997), significantly less than that in the highly deformed uppermost 200 m of Hole 735B and similar to that in the deeper, less deformed section of that hole (Dick et al., 2000).
The variability in metamorphic mineral assemblages, ranging from brown amphibole to green, fibrous amphibole and chlorite/smectite to carbonate and clay, suggests that fluid circulation and water-rock interactions continued throughout a period of progressive cooling and uplift.
www-odp.tamu.edu /publications/209_IR/chap_10/c10_3.htm   (3469 words)

  
 Mesothelioma - Amphibole   (Site not responding. Last check: 2007-10-20)
Amphibole is an important group of rock-forming minerals, very similar in chemical composition and general characters to the pyroxenes, and like them falling into three series according to the system of crystallization.
They differ from the pyroxenes, however, in having an angle between the prismatic cleavage of 56° instead of 87°; they are specifically lighter than the corresponding pyroxenes; and, in their optical characters, they are distinguished by their stronger pleochroism and by the wider angle of extinction on the plane of symmetry.
The name amphibole (from the Greek amfibolos, ambiguous) was used by R.J. Hauy to include tremolite, actinolite, and hornblende; this term has since been applied to the whole group.
mesothelioma.me.uk /Amphibole.html   (462 words)

  
 USGS Geology in the Parks
A bright to gray-green member of the amphibole mineral family.
Amphibole minerals generally contain iron, magnesium, calcium and aluminum in varying amounts, along with water.
Hornblende always has aluminum and is a most common dark green to fl variety of amphibole; it, forms forming in many igneous and metamorphic rocks.
wrgis.wr.usgs.gov /docs/parks/misc/glossaryAtoC.html   (650 words)

  
 amphibole on Encyclopedia.com
The amphibole minerals are closely related in crystal structure, but they crystallize in two different systems, orthorhombic and monoclinic; their close structural relationship is reflected in uniform prism angles of about 56° and 124° and in good cleavages parallel to these prisms.
The amphibole minerals are found both in igneous and metamorphic rocks.
Pleural mesothelioma cases in Biancavilla are related to a new fluoro-edenite fibrous amphibole.
www.encyclopedia.com /html/a1/amphibol.asp   (382 words)

  
 Read about Amphibole at WorldVillage Encyclopedia. Research Amphibole and learn about Amphibole here!   (Site not responding. Last check: 2007-10-20)
In chemical composition and general characteristics they are very similar to the pyroxenes and, like them, fall into three series according to their system of
Amphiboles are also specifically less dense than the corresponding pyroxenes, and in their optical characteristics they are distinguished by their stronger
Amphiboles are minerals of either original or secondary origin; in the former case occurring as constituents (
encyclopedia.worldvillage.com /s/b/Amphibole   (442 words)

  
 The Minerals of Igneous Rocks
Biotite is differentiated from amphibole by shape of the crystals (hexagonal for biotite and elongated or needle-like for amphibole) and by hardness (biotite is soft, amphibole is hard).
Amphibole is a rather common mineral in all igneous rocks, however, it is only abundant in the intermediate igneous rocks.
Biotite and amphibole do occur together in igneous rocks, but the association is not all that common.
geology.csupomona.edu /alert/igneous/igmin.htm   (1142 words)

  
 GemRocks: Amphibole-Rich Rocks
By definition, both consist largely of an amphibole; they differ in that amphibolite has plagioclase feldspar as its second most abundant constituent whereas amphibole gneiss has quartz in that secondary role.
Although the amphiboles constitute the major portion of this rock, their compositions are such that this rock should not be considered to be nephrite or jade.
The word amphibole was first applied to minerals of this group in 1801 by the famous French mineralogist Abbé René-Just Haüy (1743-1822).
www.cst.cmich.edu /users/dietr1rv/amphibole.htm   (1029 words)

  
 MSN Encarta - Search Results - Amphibole Minerals
Amphibole Minerals, large, extremely complex group of rock-forming silicates that are widely distributed in igneous and metamorphic rocks.
Silicate minerals comprise about one third of all known natural crystalline materials, and 95 per cent of the rocks of the Earth’s crust consist of...
Hornblende, the most common group, or series, of amphibole minerals, distributed widely in metamorphic and igneous rocks.
uk.encarta.msn.com /Amphibole_Minerals.html   (101 words)

  
 Practical Thermobarometry Part 2: Mineral Groups - amphibole   (Site not responding. Last check: 2007-10-20)
The amphibole structure is related to that of the pyroxenes, and consists of double chains of tetrahedra along the c axis, a pair of chains with apices facing each other forming a broad I-beam.
The amphibole formula unit has a large number of sites and great flexibility of substitution, but in getting familiar with the amphiboles it will help to bear in mind the comparisons indicated above with pyroxene and mica.
Because amphiboles have no fixed cation total, and may have variable OH content (so no fixed cationic charge), there is no simple method for formula and ferric iron recalculation.
www.earth.ox.ac.uk /~davewa/pt/pt02_amp.html   (669 words)

  
 ATSDR - Asbestos - What Is Asbestos   (Site not responding. Last check: 2007-10-20)
Some studies show that amphibole fibers stay in the lungs longer than crystotile, and this tendency may account for their increased toxicity (harmfulness to the body).
Mining activities — Exposure to tremolite asbestos (a type of amphibole asbestos) can occur in workers involved in mining, milling, and handling of other ores and rocks containing tremolite asbestos (such as vermiculite or talc).
Amphibole asbestos has been found in some vermiculite sources used as home and building insulation.
www.atsdr.cdc.gov /asbestos/asbestos_whatis.html   (805 words)

  
 Amethyst Galleries - AMPHIBOLE GROUP
The amphiboles represent the majority of the double-chained inosilicates.
Amphiboles form at lower temperatures with the presence of water; always at the expense of the their single chained cousins, the pyroxenes.
The amphiboles are a rather large group with over 60 recognized members; mostly because of chemical differences.
mineral.galleries.com /minerals/silicate/amphibol.htm   (229 words)

  
 Mortality in a cohort of vermiculite miners exposed to fibrous amphibole in Libby, Montana -- McDonald et al. 61 (4): ...
Mortality in a cohort of vermiculite miners exposed to fibrous amphibole in Libby, Montana -- McDonald et al.
Mortality in a cohort of vermiculite miners exposed to fibrous amphibole in Libby, Montana
The mortality of amphibole miners in South Africa, 1946–80.
oem.bmjjournals.com /cgi/content/full/61/4/363   (2542 words)

  
 Amphibole - Structure, crystal chemistry, and provenance
Amphiboles are common rock-forming minerals in the earth’s crust.
Much of the crystal-chemical behavior of amphiboles can be considered in this light: the M2 and M4 amphiboles sites are equivalent to the M1 and M2 sites, respectively, of the pyroxene structure.
Because amphiboles show extensive solid solution, many aspects of their composition are controlled by the host rock chemistry.
www.geol.lsu.edu /henry/Geology7900/Amphibole/Amphibole.htm   (560 words)

  
 OFR-03-128: USGS Spectroscopy Lab - Reflectance Spectroscopy as a Rapid Assessment Tool   (Site not responding. Last check: 2007-10-20)
It is acceptable for the method to not detect the amphibole when it is present as long as conditions can be identified to flag such a "not detectable" condition that would indicate another test is necessary.
Figure 7c: Amphibole grains from the Libby, MT jump from the ceramic pestle to a rubber glove due to electrostatic charge.
We estimate amphibole detection should, in general, be improved approximately linearly with improvements in spectral resolution from 0.011 to at least 0.002 micron, or about a factor of 5.
pubs.usgs.gov /of/2003/ofr-03-128/ofr-03-128.html   (7172 words)

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