Augite Mineral Data

General Augite Information

Chemical Formula:

(Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6

Composition:

Molecular Weight = 236.35 gm

Sodium 0.97 % Na 1.31 % Na₂O

Calcium 15.26 % Ca 21.35 % CaO

Magnesium 9.26 % Mg 15.35 % MgO

Titanium 2.03 % Ti 3.38 % TiO₂

Aluminum 4.57 % Al 8.63 % Al₂O₃

Iron 4.73 % Fe 6.08 % FeO

Silicon 22.58 % Si 48.30 % SiO₂

Oxygen 40.62 % O

______ ______

100.00 % 104.40 % = TOTAL OXIDE

Empirical Formula:

Ca_0.9Na_0.1Mg_0.9Fe²⁺_0.2Al_0.4Ti_0.1Si_1.9O₆

Environment:

Basic igneous and metamorphic rocks.

IMA Status:

Valid Species (Pre-IMA) 1792

Locality:

Common world wide. Link to MinDat.org Location Data.

Name Origin:

From the Greek auge - "luster."

Name Pronunciation:

Augite

Synonym:

Fassaite

ICSD 9257

PDF 24-203

Augite Image

Images:

Augite

Comments: Clear, dark gray augite prisms in matrix.
Location: Isle of Ischia, near Naples, Compania, Italy. Scale: Size Not Given.
© Lou Perloff / Photo Atlas of Minerals

Images:

Calzirtite Augite Richterite

Comments: Gray irregular grain of calzirtite (see arrow) in fibrous augite with dark red richterite.
Location: Jacupiranga Mine, Cajati, Sao Paulo, Brazil. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Tuscanite Augite

Comments: Translucent tuscanite microcrystal in in vug in low-Fe augite (var. fassaite).
Location: Pitigliano Quarry, Grosseto, Tuscany, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Augite Crystallography

Axial Ratios:

a:b:c =1.0888:1:0.5833

Cell Dimensions:

a = 9.8, b = 9, c = 5.25, Z = 4; beta = 105° V = 447.27 Den(Calc)= 3.51

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 1.43(1), 1.62(1), 2.99(1),

Forms:

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Forms: ( 0 1 0) ( 1 1 0) ( 1 1 1) ( 1 0 0)

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Physical Properties of Augite

Cleavage:

{110} Perfect, {010} Indistinct

Color:

Brown green, Green, Light brown, Dark brown, Black.

Density:

3.2 - 3.6, Average = 3.4

Diaphaneity:

Translucent to opaque

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Columnar - Forms columns

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Massive - Fibrous - Distinctly fibrous fine-grained forms.

Hardness:

5-6.5

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Resinous

Streak:

greenish gray

Optical Properties of Augite

Gladstone-Dale:

CI meas= 0.066 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.095 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2,KPDmeas= 0.2065,KC= 0.2211
Ncalc = 1.71 - 1.8

Optical Data:

Biaxial (+), a=1.68-1.703, b=1.684-1.711, g=1.706-1.729, bire=0.0260, 2V(Calc)=48-68, 2V(Meas)=40-52. Dispersion weak to distinct, r > v.

Pleochroism (x):

pale green, pale brownish green, pale bluish green, bluish green, or pale purple brown.

Pleochroism (y):

pale brownish green, pale greenish brown, pink, or yellowish green.

Calculated Properties of Augite

Electron Density:

Bulk Density (Electron Density)=3.37 gm/cc
note: Specific Gravity of Augite =3.40 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Augite= 4.80 barns/electron
U=PE_Augite x rElectron Density= 16.17 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Augite is Not Radioactive

Augite Classification

Dana Class:

65.01.03a.03 (65)Inosilicate Single-Width Unbranched Chains, W=1

(65.01)with chains P=2

(65.01.03a)C2/c clinopyroxenes (Ca clinopyroxenes)

65.01.03a.01 Diopside CaMgSi2O6 C 2/c 2/m

65.01.03a.02 Hedenbergite CaFeSi2O6 C 2/c 2/m

65.01.03a.03 Augite (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6 C 2/c 2/m

65.01.03a.04 Johannsenite CaMnSi2O6 C 2/c 2/m

65.01.03a.05 Petedunnite Ca(Zn,Mn,Fe,Mg)Si2O6 C 2/c 2/m

65.01.03a.06 Esseneite CaFeAlSiO6 C 2/c 2/m

65.01.03a.07 Davisite! Ca(Sc,Ti,Mg,Ti)AlSiO6 C 2/c 2/m

Strunz Class:

09.DA.15 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DA -Inosilicates with 2-periodic single chains, Si2O6; pyroxene family

09.DA.15 Augite (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6 C 2/c 2/m

09.DA.15 Esseneite CaFeAlSiO6 C 2/c 2/m

09.DA.15 Diopside CaMgSi2O6 C 2/c 2/m

09.DA.15 Johannsenite CaMnSi2O6 C 2/c 2/m

09.DA.15 Hedenbergite CaFeSi2O6 C 2/c 2/m

09.DA.15 Petedunnite Ca(Zn,Mn,Fe,Mg)Si2O6 C 2/c 2/m

09.DA.15 Davisite! Ca(Sc,Ti,Mg,Ti)AlSiO6 C 2/c 2/m

Other Augite Information

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Print or Cut-and-Paste your Augite Specimen Label here :

Augite

(Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6
Dana No: 65.01.03a.03 Strunz No: 09.DA.15
Locality:

Notes:

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