Orthoclase Mineral Data

Orthoclase Mineral Data
Search Webmineral :
   
Home Crystal jmol jPOWD Chem X Ray Dana Strunz Properties A to Z Images Share
      News Help About

Advertisment
McDougall Minerals is based near famous Bancroft, Ontario, at the heart of one of the best mineral regions in Canada

General Orthoclase Information

Help on Chemical Formula: Chemical Formula: KAlSi3O8
Help on Composition: Composition: Molecular Weight = 278.33 gm
   Potassium  14.05 %  K    16.92 % K2O
   Aluminum    9.69 %  Al   18.32 % Al2O3
   Silicon    30.27 %  Si   64.76 % SiO2
   Oxygen     45.99 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: KAlSi3O8
Help on Environment: Environment: Intrusive and extrusive igneous, and metamorphic rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1823
Help on Locality: Locality: Common world wide occurrences. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek orthos - "right" and kalo -" I cleave" in allusion to the mineral's right angle of good cleavage.
Help on Name Pronunciation: Name Pronunciation: Orthoclase + Pronunciation Say ORTHOCLASE
Help on Synonym: Synonym: Adularia
  Orthose
 

Orthoclase Image

Click Here for Larger Orthoclase Image in a New Browser Window Images:
Click Here for Larger Orthoclase Image

Orthoclase   Lorenzenite

Comments: Striated, dark violet crystal of lorenzenite in cream-colored orthoclase.
Location: Khibiny Massif, Kola Peninsula, Russia. Scale: 1.3 x 1.2 cm.
© John Veevaert
Click Here for Larger Orthoclase Image in a New Browser Window Images:
Click Here for Larger Orthoclase Image

Orthoclase

Comments: Carlsbad twinned crystal of orthoclase. Former Martín Oliete Fontela collection.
Location: Zarzalejo, Madrid. Scale: 5.2x4.6x2.2 cm.
© Fabre Minerals
Click Here for Larger Orthoclase Image in a New Browser Window Images:
Click Here for Larger Orthoclase Image

Orthoclase

Comments: Gemmy, twinned adularia (orthoclase) specimen on matrix. Former Bally Museum collection.
Location: Rhonegletscher, Switzerland. Scale: Crystal size 3 x 2 cm.
© Fabre Minerals

Orthoclase Crystallography
Help on Axial Ratios: Axial Ratios: a:b:c =0.6636:1:0.5534
Help on Cell Dimensions: Cell Dimensions: a = 8.625, b = 12.996, c = 7.193, Z = 4; beta = 116.016° V = 724.57 Den(Calc)= 2.55
Help on Crystal System: Crystal System: Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.18(1), 4.02(0.9), 3.8(0.8),
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: ( 1 1 0) ( 1 0 1) ( 0 0 1) ( 0 1 0)

Warning: this large pop-up is very compute intensive and may not work well with some computers.
Click Here for Large Orthoclase Structure Window Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
 Help on Above


Colville A A , Ribbe P H , American Mineralogist , 53 (1968) p.25-37, The crystal structure of an adularia and a refinement of the structure of, orthoclase, Note: Spencer B, variety adularia

View Additional jPOWD Structure files for Orthoclase
[1] [2] [3] [4] [5] [6]
 

Physical Properties of Orthoclase

Help on Cleavage: Cleavage: {001} Perfect, {010} Good
Help on Color: Color: Colorless, Greenish, Grayish yellow, White, Pink.
Help on Density: Density: 2.56
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: Blocky - Crystal shape tends to be equant (e.g. feldspars).
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
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 Orthoclase

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.011 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.007 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2044,KPDmeas= 0.2036,KC= 0.2058
Ncalc = 1.52 - 1.53
Help on Optical Data: Optical Data: Biaxial (-), a=1.518, b=1.522, g=1.523-1.524, bire=0.0050-0.0060, 2V(Calc)=52-70, 2V(Meas)=65-75. Dispersion relatively strong.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
 

Calculated Properties of Orthoclase

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.53 gm/cc
note: Specific Gravity of Orthoclase =2.55 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEOrthoclase = 2.85 barns/electron
U=PEOrthoclase x relectron= 7.20 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 200.97 (Gamma Ray American Petroleum Institute Units)
Concentration of Orthoclase per GRapi unit = 0.50 (%)

Estimated Radioactivity from Orthoclase - barely detectable

 

Orthoclase Classification
Help on Dana Class: Dana Class: 76.01.01.01 (76)Tectosilicate Al-Si Framework
  (76.01)with Al-Si frameworks
  (76.01.01)K (Na,Ba) feldspars
 
76.01.01.01 Orthoclase KAlSi3O8 C 2/m 2/m
 
76.01.01.02 Sanidine (K,Na)(Si,Al)4O8 C 2/m 2/m
 
76.01.01.03 Hyalophane (K,Ba)Al(Si,Al)3O8 C 2/m 2/m
 
76.01.01.04 Celsian BaAl2Si2O8 I21/c 2/m
 
76.01.01.05 Microcline KAlSi3O8 C1 1
 
76.01.01.06 Anorthoclase (Na,K)AlSi3O8 C1 1
 
76.01.01.07 Rubicline! (Rb,K)AlSi3O8 P1 1
 
76.01.01.08 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 Orthoclase Information
Help on See Also: See Also: Links to other databases for Orthoclase :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Amethyst Galleries' Mineral Gallery
5 - Athena
6 - CalTech Mineral Spectroscopy
7 - EUROmin Project
8 - Ecole des Mines de Paris
9 - Franklin Minerals(Dunn)
10 - GeoScienceWorld
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 - Minerals in Thin Sections-Humboldt State
20 - Online Mineral Museum
21 - QUT Mineral Atlas
22 - Ruff.Info
23 - Tradeshop.com - The Rainbow of Gems
24 - UCLA - Petrography Thin-Sections
25 - WWW-MINCRYST

Search for Orthoclase using:

Google
 
Web webmineral.com
[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Orthoclase :

Adam's Minerals Google Search for Orthoclase
Dakota Matrix Minerals Google Search for Orthoclase
John Betts Fine Minerals Search for Orthoclase
McDougall Minerals Google Search for Orthoclase
Rock and Mineral Shows Google Search for Orthoclase
Tucson Mall Google Search for Orthoclase
Weinrich Minerals, Inc. Google Search for Orthoclase

Ask about Orthoclase here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Orthoclase

KAlSi3O8
Dana No: 76.01.01.01 Strunz No: 09.FA.30
Locality:

 

Notes: