PRESENTING byAzhar mahmood”

PYROXENE GROUP OF MINERALS

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

HISTORYNamed 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.

INTRODUCTION

Pyroxene is found in extrusive igneous rocks.

Like :BASALT, DECITE

Pyroxene is found in intrusive igneous rocks.

Like: DIORIT,GABBRO

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

ORTHOPYROXENECa2Si2O6 Walxonite

Mg2Si2O6 Fe2Si2O6

ENSTATITE FERROSILITE

Hypersthene50 MOL %

5 MOL % 5 MOL %

CLINOPYROXENESWollastonite Ca2Si2O6

Mg2Si2O6 Fe2Si2O650 mol %

5 mol %10 mol %Pigeonite

Diopside Hedenbergite50 mol % CaMgSi2O6

55 mol %CaFeSi2O6

AUGITE

The grey areasrepresent miscbility gap..

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.

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.

USES• A pyroxene is an

important mined source of lithium, used in heat-resistant ceramics, medication, and batteries.