Mineralogy Database

Anorthite Mineral Data

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General Anorthite Information

Help on Chemical  Formula: Chemical Formula: CaAl2Si2O8
Help on Composition: Composition: Molecular Weight = 277.41 gm
   Sodium     0.41 %  Na    0.56 % Na2O
   Calcium   13.72 %  Ca   19.20 % CaO
   Aluminum  18.97 %  Al   35.84 % Al2O3
   Silicon   20.75 %  Si   44.40 % SiO2
   Oxygen    46.14 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na0.05Ca0.95Al1.95Si2.05O8
Help on Environment: Environment: Magmatic and metamorphic rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1823
Help on Locality: Locality: Monte Somma and Valle di Fassa, Italy. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek, an + orthos, "not upright" in allusion to the oblique crystals.
Help on Name Pronunciation: Name Pronunciation: Anorthite + Pronunciation Say ANORTHITE
Help on Synonym: Synonym: Ab0
  An100
  ICSD 654
  Indianite
  PDF 41-1486
 

Anorthite Image

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  Anorthite   Plagioclase

Comments: Opaque white crystal of anorthite with dark brown solidified lava coating.
Location: Miyake-jima, Shizuoka, Japan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Anorthite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.635:1:1.1003
Help on Cell Dimensions: Cell Dimensions: a = 8.177, b = 12.877, c = 14.169, Z = 8; alpha = 93.166°, beta = 115.85°, gamma = 91.216° V = 1,340.29 Den(Calc)= 2.75
Help on Crystal System: Crystal System: Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1,I1
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.2(1), 3.18(0.75), 4.04(0.6),
Help on Forms: Forms:

Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

Keyboard
S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

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

Warning: this java applet does not work in some browsers because of security restrictions.

 

Physical Properties of Anorthite

Help on Cleavage: Cleavage: {001} Perfect, {010} Good
Help on Color: Color: Colorless, Gray, White, Red, Reddish gray.
Help on Density: Density: 2.72 - 2.75, Average = 2.73
Help on Diaphaneity: Diaphaneity: Transparent to Subtransparent to translucent
Help on Fracture: Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Help on Habit: Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form.
Help on Habit: Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Help on Habit: Habit: Striated - Parallel lines on crystal surface or cleavage face.
Help on Hardness: Hardness: 6 - Orthoclase
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white
 

Optical Properties of Anorthite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.02 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.015 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.211,KPDmeas= 0.2121,KC= 0.2079
Ncalc = 1.57
Help on Optical Data: Optical Data: Biaxial (-), a=1.572-1.576, b=1.5785-1.5832, g=1.583-1.588, bire=0.0110-0.0120, 2V(Calc)=78, 2V(Meas)=78. Dispersion relatively weak.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
 

Calculated Properties of Anorthite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.73 gm/cc
note: Specific Gravity of Anorthite =2.75 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEAnorthite = 3.05 barns/electron
U=PEAnorthite x rElectron Density= 8.32 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Anorthite is Not Radioactive
 

Anorthite Classification

Help on  Dana Class: Dana Class: 76.01.03.06 (76)Tectosilicate Al-Si Framework
  (76.01)with Al-Si frameworks
  (76.01.03)Plagioclase series
 
76.01.03.00 Plagioclase* (Na,Ca)(Si,Al)4O8 C1 1
 
76.01.03.01 Albite NaAlSi3O8 C1 1
 
76.01.03.02 Oligoclase (Na,Ca)(Si,Al)4O8 C1 1
 
76.01.03.03 Andesine* (Na,Ca)(Si,Al)4O8 C1 1
 
76.01.03.04 Labradorite* (Ca,Na)(Si,Al)4O8 C1 1
 
76.01.03.05 Bytownite* (Ca,Na)(Si,Al)4O8 C1 1
 
76.01.03.06 Anorthite CaAl2Si2O8 P1,I1 1
Help on  Strunz Class: Strunz Class: 09.FA.35 09 - SILICATES (Germanates)
  09.F - Tektosilicates without Zeolitic H2O
  09.FA -Tektosilicates without additional non-tetrahedral anions, (Al,B):Si = 1:1
 
09.FA.35 Albite NaAlSi3O8 C1 1
 
09.FA.35 Bytownite* (Ca,Na)(Si,Al)4O8 C1 1
 
09.FA.35 Anorthite CaAl2Si2O8 P1,I1 1
 
09.FA.35 Andesine* (Na,Ca)(Si,Al)4O8 C1 1
 
09.FA.35 Labradorite* (Ca,Na)(Si,Al)4O8 C1 1
 
09.FA.35 Oligoclase (Na,Ca)(Si,Al)4O8 C1 1
 
09.FA.35 Reedmergnerite NaBSi3O8 C1 1
 
09.FA.35 Plagioclase* (Na,Ca)(Si,Al)4O8 C1 1
 

Other Anorthite Information

Help on See Also: See Also: Links to other databases for Anorthite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - Franklin Minerals(Dunn)
7 - Franklin Minerals(Palache)
8 - GeoScienceWorld
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - HyperPhysics
14 - MinDAT
15 - Mineral and Gemstone Kingdom
16 - Mineralienatlas (Deutsch)
17 - Online Mineral Museum
18 - QUT Mineral Atlas
19 - Ruff.Info
20 - UCLA - Petrography Thin-Sections
21 - WWW-MINCRYST

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

Anorthite

CaAl2Si2O8
Dana No: 76.01.03.06 Strunz No: 09.FA.35
Locality:

 

Notes:

 

 


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