Identification Chart for the Rock-Forming Minerals by Polarizing Microscope

(Revised April 15, 2002)

by Akira ISHIWATARI

Department of Earth Sciences, Faculty of Science, Kanazawa University, Kanazawa 920-1192 JAPAN


The chart presented below is a colored version of that included in A. Ishiwatari's paper published in the Journal of the Geological Society of Japan, Vol. 105, No. 2, p. 156-158 (1999) (hereafter referred to as "journal chart"). The chart is also published as a colored hard plastic plate associated with an interference color chart (Michel Lvy's chart) from the Geological Society of Japan (hereafter referred to as "plastic chart").  Please ask the Geological Society of Japan for purchase of the plastic plate ($2) and copyright permission. The table given below is only for personal use.

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Errata (The errors listed here are already corrected in the chart below) (020415 added)
1. (Journal chart) Kyanite (E3) is _ (low-angle extinction, negative sign), not - (straight extinction, negative sign).
2. (Journal and plastic charts) "Sapphyrine" (E4) is wrong. "Sapphirine" is correct.
3. (Journal and plastic charts) Prehnite (D3) is - (straight extinction, negative sign), not _ (low-angle extinction, negative sign).


  A B C D E F G H
Optic Axial Angle 2Vz
Optic Character
Optically

Isotropic

0 20 60          90 -60 -20 -0 Most Important Minerals
Uniaxial Biaxial Optically Anisotropic Biaxial Uniaxial
Plane-Polarized Light Positive Positive Conoscopic Observation Negative Negative Crossed Polarized Light
1 Colorless Refractive

Index Low

Cleavage

Obscure

(*Cleavage

Distinct)

n<=1.54-1.58

Fluorite* Chabazite Cryolite Mordenite-* Wairakite Stilbite$* Chabazite Elongation Sign
+ / -
Opal Heulandite_* Clinoptilolite* Tridymite Epistilbite^* Scolecite_* Sepiolite+* Straight Extinction +/-
Cristobalite Chalcedony
-/+
Thomsonite$ Natrolite + Fenaksite Laumontite^* Cristobalite Low-angle Extinction ^/_
Analcite Leucite GypsumX* Mesolite$* Canasite* Orthoclase*

(Perthite)

Cancrinite* High-angle Extinction X
Sodalite F,OH Apophyllite Na Phillipsite^* Microcline#* Kaliophilite
Kalsilite
Elongation both signs $
Nosean(gray) Quartz Catapleite* Low Ab, An50-80 Plagioclase =* Sanidine* Nepheline Twins
Cement Resin Xonotlite+* Anhydrite+* Petalite* Cordierite - Anortho-
clase #*
Scapolite-* Polysynthetic =
2 Colorless Refractive

Index High

Cleavage

Obscure

Zunyite Eudialyte Topaz + Pectolite Andalusite - Boehmite Beryl - Polysynth. in 2 directions #
Helvite Phenakite Mullite + Chondrodite Danburite% Serpentine^ Corundum- Birefringence(Interference)
Garnet
MgAl pink
CaAl yel.
FeAl red
CaFe brown
MnAl red
CaCr green
Melilite + (kermanite) Sillimanite + (Clino)Humite Datolite Kaolinite^ Melilite-(Gehlenite) Small (Low)
Pumpellyite Chrysoberyl Axinite Smectite
0-30o
Medium (Med)
Stishovite Larnite Fo Olivine Fo<90 Pyrophyllite + Apatite- Large (High)
Zircon + Titanite(Sphene)% Diaspore Monticellite Lepidolite+ Vesuvianite Abnormal Inter-
ference Color
3 Colorless Refractive

Index High

Cleavage

Distinct

  Alunite Coesite 65o Prehnite- Tremolite^ Margarite+ Talc + 15o Conoscopic Dispersion Strong %
Brucite Barite Celestite Lawsonite- Cumming-
tonite
^=
Paragonite+ Phengite+ Sericite Illite PPL Color Zoning Distinct @
(Clino)Zoisite$ Antho-
phyllite+
Gedrite Grunerite Musco-
vite +
Phengite+  
Periclase Kotoite 21o AugiteX En Orthopyroxene+ En<85 Wollastonite$ Calcite Dolomite Opaque Minerals(Reflection)
Diamond PigeoniteX DiopsideX JadeiteX Kyanite^ Aragonite Magnesite Siderite Ilmenite (black, platy, ani)
4 Blue-Purple Fluorite Scheelite Clinoenstatite Rhodonite(red) Lazulite Arfvedsonite-@ Magnetite (bk, bulky, iso)
Hauyne Osumilite Chloritoid _=
(Blue Green, Green)
Sapphirine% Glaucophane^@ Crossite$@ Hematite (red transl. ani)
Lazurite Yoderite Turquoise Azurite Riebeckite _ $ Winchite Tourmaline+(highly pleochroic) Pyrite (yellow, bulky, iso)
5 Brown Perovskite Melanite@ Cassiterite@Thorite Monazite Aenigmatite Perovskite Melanite Allanite $@ Barkevikite Chalcopyrite (yel. bul. ani)
Cr-Spinel Chromite Brookite @% Titanite(Sphene)% Pargasite^ Common Horn-
blende^
Richterite Biotite+ Phlogopite Stilpnomelane Pyrrhotite (brown, platy, ani)
6 Green-Blue Green Al-Spinel Hercynite   Antlerite OmphaciteX% Barroisite^ Graphite (black, platy, ani)
Manganosite Chlorite_ Heden-
bergiteX
Aegirine Augite @ Actinolite^ Malachite Chlorite^ isotropic/ anisotropic
7 Yellow-Yellow Green Pyrochlore Xenotime-Y Pumpellyite$ Staurolite^ Aegirine^@ Serpentine^ Glauconite^ Compiled by
A. Ishiwatari
Dept. of Earth
Sciences
Kanazawa
University
Limonite Helvite Rutile Lampro-
phyllite
Astrophyllite Epidote $ Pistacite $@ Anatase
8 Red-Red Purple-Pink Garnet Cuprite Eudialyte Titan-
augiteX@
Piemontite$@ Hyper-
sthene+
Bustamite Biotite+
Hematite

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99/03/02 established, 03/08/26 revised