Introduction to MineralogyDr. Tark Hamilton

Chapter 5: Lecture 19Minerals &

Mineral Chemical Compositions

Camosun College GEOS 250

Lectures: 9:30-10:20 M T Th F300

Lab: 9:30-12:20 W F300

Pyroxene Analysis (Augite)

Diopside CaMgSi2O6 (2/m) monoclinic Kunar, Afghanistan

Fabreminerals

Orthopyroxene & Olivineon 2 triangular diagrams

(MgO-SiO2-FeO) Wt% oxides

(Mg-Si-Fe) Atom%En Fs

Fo Fa

Pyroxene Triangle (En-Wo-Fs)

Augite

Pigeonite

Hypersthene

Salite

Di Hd

En Fs

Wo

Amphibole Analysis

Basaltic Hornblende twin (100)

Linear (Bar) Graphs of Composition

Molecular % (MgO-SiO2-FeO)

Periclase Wustite

Silica

Pyroxene+ Quartz

Pyroxene+ Olivine

“Silica Saturation fence”

Tie lines

Carbonate Triangle: Mol%(MgO-CaO-(FeO+MnO))

Tie Lines for coexisting phasesCalcite group:

CalciteMagnesite

SideriteRhodochrosite

SmithsoniteHexagonal R3c

Dolomite group:DolomiteAnkerite

KutnahoriteHexagonal R 3

Cc

AnkDol

Mag Sid

Rhodochrosite, Quartz & TetrahedriteSweethome Mine CO, Fabreminerals

Stalactites, Catamarca Argentina

Kristalle & Crys

Knut Eldjarn

Py

Ternary Plot: Feldspar Composition

Alkali Feldspars

Plagioclase

Anorthoclase

Sanidine

Solvus

Blue Celsian BaAl2Si2O8

Franklin NJ, Peter Cristofono 2008