Mineralogy Database

Oligoclase Mineral Data

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General Oligoclase Information

Help on Chemical  Formula: Chemical Formula: (Na,Ca)(Si,Al)4O8
Help on Composition: Composition: Molecular Weight = 265.42 gm
   Sodium     6.93 %  Na    9.34 % Na2O
   Calcium    3.02 %  Ca    4.23 % CaO
   Aluminum  12.20 %  Al   23.05 % Al2O3
   Silicon   29.63 %  Si   63.38 % SiO2
   Oxygen    48.22 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na0.8Ca0.2Al1.2Si2.8O8
Help on Environment: Environment: Magmatic and pegmatitic rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1826
Help on Locality: Locality: Twedestrand, Norway. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek, oligos and kasein, "little cleavage."
Help on Name Pronunciation: Name Pronunciation: Oligoclase + Pronunciation Say OLIGOCLASE
Help on Synonym: Synonym: Ab80
  An20
  Sunstone
 

Oligoclase Image

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  Oligoclase   Plagioclase

Comments: Rectangular cleavage fragment of salmon-orange oligoclase (sunstone) feldspar.
Location: Norway. Scale: 47x30x7 mm.
© John Betts - Fine Minerals

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  Oligoclase   Plagioclase

Comments: Clear glassy crystalline oligoclase with milky quartz and muscovite.
Location: Bakersville, Mitchell County, North Carolina, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Oligoclase Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.6377:1:0.6651
Help on Cell Dimensions: Cell Dimensions: a = 8.15, b = 12.78, c = 8.5, Z = 5; alpha = 94.016°, beta = 116.3333°, gamma = 88.667° V = 791.30 Den(Calc)= 2.78
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): 3.2(1), 3.74(0.8), 4.02(0.8),
Help on Forms: Forms:

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Help on Above

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

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Physical Properties of Oligoclase

Help on Cleavage: Cleavage: {001} Perfect, {010} Good
Help on Color: Color: Brown, Colorless, Greenish, Gray, Yellowish.
Help on Density: Density: 2.64 - 2.66, Average = 2.65
Help on Diaphaneity: Diaphaneity: Transparent 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 Hardness: Hardness: 7 - Quartz
Help on Luminescence: Luminescence: Fluorescent, Long UV=yellow.
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white
 

Optical Properties of Oligoclase

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.054 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1951,KPDmeas= 0.2047,KC= 0.2062
Ncalc = 1.54 - 1.57
Help on Optical Data: Optical Data: Biaxial (+), a=1.533-1.543, b=1.5368-1.5477, g=1.542-1.552, bire=0.0090, 2V(Calc)=82-86, 2V(Meas)=82. Dispersion none.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
 

Calculated Properties of Oligoclase

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.63 gm/cc
note: Specific Gravity of Oligoclase =2.65 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEOligoclase = 1.98 barns/electron
U=PEOligoclase x rElectron Density= 5.19 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Oligoclase is Not Radioactive
 

Oligoclase Classification

Help on  Dana Class: Dana Class: 76.01.03.02 (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 Oligoclase Information

Help on See Also: See Also: Links to other databases for Oligoclase :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Amethyst Galleries' Mineral Gallery
5 - Athena
6 - EUROmin Project
7 - Ecole des Mines de Paris
8 - Franklin Minerals(Dunn)
9 - GeoScienceWorld
10 - Glendale Community College
11 - Google Images
12 - Google Scholar
13 - Handbook of Mineralogy (MinSocAm)
14 - Handbook of Mineralogy (UofA)
15 - HyperPhysics
16 - MinDAT
17 - Mineral and Gemstone Kingdom
18 - Mineralienatlas (Deutsch)
19 - Online Mineral Museum
20 - Philatelic Mineralogy
21 - QUT Mineral Atlas
22 - Ruff.Info
23 - Scandinavian mineral gallery

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Oligoclase

(Na,Ca)(Si,Al)4O8
Dana No: 76.01.03.02 Strunz No: 09.FA.35
Locality:

 

Notes:

 

 


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