Mineralogy Database

Anorthoclase Mineral Data

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General Anorthoclase Information

Help on Chemical  Formula: Chemical Formula: (Na,K)AlSi3O8
Help on Composition: Composition: Molecular Weight = 266.25 gm
   Potassium   3.67 %  K     4.42 % K2O
   Sodium      6.48 %  Na    8.73 % Na2O
   Aluminum   10.13 %  Al   19.15 % Al2O3
   Silicon    31.65 %  Si   67.70 % SiO2
   Oxygen     48.07 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na0.75K0.25AlSi3O8
Help on Environment: Environment: In high-temperature sodic volcanic and hypabyssal rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1885
Help on Locality: Locality: Rather abundant worldwide. Some localities for well-characterized material include: on Pantelleria and Ustica Islands, Italy. At Larvik, Norway. From Berkum, North Rhine-Westphalia, Ge Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek for "oblique" and "fracture," descriptive of the cleavage
Help on Name Pronunciation: Name Pronunciation: Anorthoclase + Pronunciation Say ANORTHOCLASE
Help on Synonym: Synonym: ICSD 31180
  PDF 9-478
  Soda Microcline

Anorthoclase Image

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Comments: Two white crystals of anorthoclase (possibly mislabeled and actually anorthite.
Location: Kusukidani, Wakayama Prefecture, Kinki Region, Honshu island, Japan. Scale: 15x14x6 mm.
© John Betts - Fine Minerals

Anorthoclase Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.6406:1:0.5546
Help on Cell Dimensions: Cell Dimensions: a = 8.2, b = 12.8, c = 7.1, Z = 4; alpha = 90°, beta = 116°, gamma = 90° V = 669.80 Den(Calc)= 2.64
Help on Crystal System: Crystal System: Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: C1
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.211(1), 3.243(0.9), 4.106(0.16),

Physical Properties of Anorthoclase

Help on Cleavage: Cleavage: {001} Perfect, {010} Good
Help on Color: Color: Colorless, Green, Gray, Gray pink, Yellow.
Help on Density: Density: 2.57 - 2.6, Average = 2.58
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Help on Habit: Habit: Disseminated - Occurs in small, distinct particles dispersed in matrix.
Help on Habit: Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Help on Hardness: Hardness: 6 - Orthoclase
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Anorthoclase

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.027 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2001,KPDmeas= 0.2043,KC= 0.2057
Ncalc = 1.53 - 1.54
Help on Optical Data: Optical Data: Biaxial (-), a=1.519-1.529, b=1.524-1.534, g=1.527-1.536, bire=0.0070-0.0080, 2V(Calc)=64-74, 2V(Meas)=34-60. Dispersion r > v.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
Help on Pleochroism (z): Pleochroism (z): colorless.

Calculated Properties of Anorthoclase

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.56 gm/cc
note: Specific Gravity of Anorthoclase =2.59 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEAnorthoclase = 1.98 barns/electron
U=PEAnorthoclase x relectron= 5.08 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 52.50 (Gamma Ray American Petroleum Institute Units)
Concentration of Anorthoclase per GRapi unit = 1.90 (%)

Estimated Radioactivity from Anorthoclase - barely detectable


Anorthoclase Classification

Help on  Dana Class: Dana Class: (76)Tectosilicate Al-Si Framework
  (76.01)with Al-Si frameworks
  (76.01.01)K (Na,Ba) feldspars Orthoclase KAlSi3O8 C 2/m 2/m Sanidine (K,Na)(Si,Al)4O8 C 2/m 2/m Hyalophane (K,Ba)Al(Si,Al)3O8 C 2/m 2/m Celsian BaAl2Si2O8 I21/c 2/m Microcline KAlSi3O8 C1 1 Anorthoclase (Na,K)AlSi3O8 C1 1 Rubicline! (Rb,K)AlSi3O8 P1 1 Filatovite! K[(Al,Zn)2(As,Si)2O8] I2/c 2/m
Help on  Strunz Class: Strunz Class: 09.FA.30 09 - SILICATES (Germanates)
  09.F - Tektosilicates without Zeolitic H2O
  09.FA -Tektosilicates without additional non-tetrahedral anions, (Al,B):Si = 1:1
09.FA.30 Buddingtonite (NH4)AlSi3O8•0.5(H2O) P 21 or P 21/m Mono
09.FA.30 Celsian BaAl2Si2O8 I21/c 2/m
09.FA.30 Anorthoclase (Na,K)AlSi3O8 C1 1
09.FA.30 Hyalophane (K,Ba)Al(Si,Al)3O8 C 2/m 2/m
09.FA.30 Orthoclase KAlSi3O8 C 2/m 2/m
09.FA.30 Microcline KAlSi3O8 C1 1
09.FA.30 Rubicline! (Rb,K)AlSi3O8 P1 1
09.FA.30 Sanidine (K,Na)(Si,Al)4O8 C 2/m 2/m

Other Anorthoclase Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)
Help on See Also: See Also: Links to other databases for Anorthoclase :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - GeoScienceWorld
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - MinDAT
14 - Mineral and Gemstone Kingdom
15 - Mineralienatlas (Deutsch)
16 - Online Mineral Museum
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - UCLA - Petrography Thin-Sections

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Dana No: Strunz No: 09.FA.30





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