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Pyroxene group.
Introduction <ul><li>Pyroxene group includes both monoclinic and orthorhombic minerals. </li></ul><ul><li>Minerals belongi...
<ul><li>The chemical composition of the pyroxenes can be expressed by the general formula (W,X,Y) 2  Z  2  O  6  in which ...
<ul><li>Manganese is generally present in minor amounts except in the rare pyroxene Johannsenite, Ca Mn Si 2 O  6. </li></...
Monoclinic pyroxenes <ul><li>Diopside- Hedenbergite- Johannsenite </li></ul><ul><li>Ca (Mg, Fe, Mn) Si 2 O  6 </li></ul><u...
<ul><li>Augite – intermediate between diopside and  hedenbergite with some Al. </li></ul><ul><li>Pigeonite- intermediate b...
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Pyroxene

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Pyroxene

  1. 1. Pyroxene group.
  2. 2. Introduction <ul><li>Pyroxene group includes both monoclinic and orthorhombic minerals. </li></ul><ul><li>Minerals belonging to this group are ionosilicates having single chain structures. </li></ul><ul><li>These are the silicates of Ca, Na, Mg, Fe and Al. </li></ul><ul><li>The crystals are short prismatic with interfacial angles of about 87 º and 93 º. </li></ul>
  3. 3. <ul><li>The chemical composition of the pyroxenes can be expressed by the general formula (W,X,Y) 2 Z 2 O 6 in which W, X, Y ,Z indicate elements having similar ionic radii and capable of replacing each other in the structure. </li></ul><ul><li>In pyroxenes these elements may be : </li></ul><ul><li>W= Ca, Na </li></ul><ul><li>X= Mg, Fe 2+ , Mn 2+ , Li </li></ul><ul><li>Y= Al, Fe 3+ , Ti </li></ul><ul><li>Z= Si, Al. </li></ul>
  4. 4. <ul><li>Manganese is generally present in minor amounts except in the rare pyroxene Johannsenite, Ca Mn Si 2 O 6. </li></ul><ul><li>Lithium occurs as a major constituent in spodumene, Li Al Si 2 O 6 </li></ul><ul><li>ORHORHOMBIC Pyroxenes </li></ul><ul><li>Enstatite- Orthoferrosilite </li></ul><ul><li>Enstatite- Mg SiO 3 </li></ul><ul><li>Hypersthene- (Mg, Fe) SiO 3 </li></ul>
  5. 5. Monoclinic pyroxenes <ul><li>Diopside- Hedenbergite- Johannsenite </li></ul><ul><li>Ca (Mg, Fe, Mn) Si 2 O 6 </li></ul><ul><li>Aegirine – Na Fe Si 2 O 6 </li></ul><ul><li>Jadeite – Na Al Si 2 O 6 </li></ul><ul><li>Spodumene- Li Al Si 2 O 6 </li></ul><ul><li>Johannsenite- Ca Mn Si 2 O 6. </li></ul>
  6. 6. <ul><li>Augite – intermediate between diopside and hedenbergite with some Al. </li></ul><ul><li>Pigeonite- intermediate between clinoenstatite and Augite. </li></ul>

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