PYROXENE GROUP OF MINERALS

HISTORY……….
INTRO…………..
EXPLAINATION…..
IDENTIFYING……
USES………..

1. PRESENTING by Azhar mahmood”

2. PYROXENE GROUP OF MINERALS HISTORY………. INTRO………….. EXPLAINATION….. IDENTIFYING…… USES………..

3. HISTORY Named in 1796 by Rene Just Haüy from the Greek words for FIRE and STRANGER . Pyroxene was named because of its presence in a glassy or vitreous lava. Pyroxene was originally what might now be called " AUGITE ", but the name has been raised as a group name of structurally and chemically similar minerals.

4. INTRODUCTION Pyroxene is found in extrusive igneous rocks. Like : BASALT, DECITE Pyroxene is found in intrusive igneous rocks. Like: DIORIT,GABBRO

5. EXPLAINATION “ON THE BASIS OF CRYSTAL SYSTEM” On the basis of crystal system PYROXENE subdivided into 2 groups. PYROXENE Orthopyroxenes (Orthorhombic) Clinopyroxenes (Monoclinic) ( FeMg )2Si2O6 Ca( MgFe )Si2O6

6. ORTHOPYROXENE Ca2Si2O6 Walxonite Mg2Si2O6 Fe2Si2O6 ENSTATITE FERROSILITE Hypersthene 50 MOL % 5 MOL % 5 MOL %

7. CLINOPYROXENES Wollastonite Ca2Si2O6 Mg2Si2O6 Fe2Si2O6 50 mol % 5 mol % 10 mol % Pigeonite Diopside Hedenbergite 50 mol % CaMgSi2O6 55 mol % CaFeSi2O6 AUGITE The grey areas represent miscbility gap..

8. IDENTIFYING ORTHOPYROXENE All pyroxenes are biaxial. Opx has p low birefringence (first order red maximum) and good cleavage. ‐ Section parallel to c = 1 cleavage. ‐ Section perpendicular to c = 2. Weakly coloured (pink or green), generally colourless . Weak pale green, pale red, or pale purple pleochroism in some grains.

9. IDENTIFYING CLINOPYROXENE All pyroxenes are biaxial. Cpx has low birefringence (blues to yellow maximum) and good cleavage. ‐ Section parallel to c = 1 cleavage. ‐ Section perpendicular to c = 2. Colourless to grey, or pale green/brown, with variation associated with pleochroism . More Fe‐rich species – higher pleochroism .

10. USES A pyroxene is an important mined source of lithium, used in heat-resistant ceramics, medication, and batteries.