Mineralogy Database

Slawsonite Mineral Data

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General Slawsonite Information

Help on Chemical  Formula: Chemical Formula: (Sr,Ca)Al2Si2O8
Help on Composition: Composition: Molecular Weight = 309.65 gm
   Strontium  22.64 %  Sr   26.77 % SrO
   Calcium     1.29 %  Ca    1.81 % CaO
   Aluminum   15.68 %  Al   29.64 % Al2O3
   Silicon    19.05 %  Si   40.75 % SiO2
   Oxygen     41.34 %  O
             ______        ______ 
             100.00 %       98.97 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Sr0.8Ca0.1Al1.8Si2.1O8
Help on Environment: Environment: In pectolite veinlets in metamorphosed xenoliths.
Help on IMA Status: IMA Status: Approved IMA 1977
Help on Locality: Locality: From the Wallowa Mountains, Wallowa County, Oregon, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Chester Baker Slawson (1898-1964, Mineralogist AT THE University of Michigan, Ann Arbor, Michigan, USA.
Help on Name Pronunciation: Name Pronunciation: Slawsonite + Pronunciation Say SLAWSONITE
Help on Synonym: Synonym: ICSD 100141
  PDF 37-462

Slawsonite Image

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Comments: White crystalline slawsonite in rock.
Location: Sarisaka, Kagami, Kochi, Japan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Slawsonite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.9511:1:0.891
Help on Cell Dimensions: Cell Dimensions: a = 8.888, b = 9.344, c = 8.326, Z = 4; beta = 90.33° V = 691.46 Den(Calc)= 2.97
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/a
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.708(1), 2.917(0.7), 3.498(0.64),

Physical Properties of Slawsonite

Help on Cleavage: Cleavage: {001} Good, {010} Fair
Help on Color: Color: Colorless, Medium gray.
Help on Density: Density: 3.05 - 3.5, Average = 3.27
Help on Diaphaneity: Diaphaneity: Semitransparent
Help on Habit: Habit: Aggregates - Made of numerous individual crystals or clusters.
Help on Habit: Habit: Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Help on Habit: Habit: Tabular - Form dimensions are thin in one direction.
Help on Hardness: Hardness: 5.5-6.5 - Knife Blade-Pyrite
Help on Luminescence: Luminescence: Fluorescent, Short UV=pinkish red purple.
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Slawsonite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.062 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= -0.034 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1951,KPDmeas= 0.1769,KC= 0.1887
Ncalc = 1.56 - 1.66
Help on Optical Data: Optical Data: Biaxial (-), a=1.57-1.573, b=1.581-1.582, g=1.585-1.586, bire=0.0130-0.0150, 2V(Calc)=60-66, 2V(Meas)=55-82. Dispersion r < v medium.

Calculated Properties of Slawsonite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.86 gm/cc
note: Specific Gravity of Slawsonite =2.97 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.02
Boson Index = 0.98
Help on Photoelectric: Photoelectric: PESlawsonite = 26.20 barns/electron
U=PESlawsonite x rElectron Density= 74.99 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Slawsonite is Not Radioactive

Slawsonite Classification

Help on  Dana Class: Dana Class: (76)Tectosilicate Al-Si Framework
  (76.01)with Al-Si frameworks
  (76.01.05)Paracelsian group Paracelsian BaAl2Si2O8 P 21/c 2/m Slawsonite (Sr,Ca)Al2Si2O8 P 21/a 2/m
Help on  Strunz Class: Strunz Class: 09.FA.50 09 - SILICATES (Germanates)
  09.F - Tektosilicates without Zeolitic H2O
  09.FA -Tektosilicates without additional non-tetrahedral anions, (Al,B):Si = 1:1
09.FA.50 Slawsonite (Sr,Ca)Al2Si2O8 P 21/a 2/m

Other Slawsonite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2) OPTIC PROP.(AntBidBlaNic2)
Help on See Also: See Also: Links to other databases for Slawsonite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 09.FA.50





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