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Scawtite Mineral Data

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General Scawtite Information

Help on Chemical  Formula: Chemical Formula: Ca7Si6(CO3)O18•2(H2O)
Help on Composition: Composition: Molecular Weight = 833.09 gm
   Calcium   33.68 %  Ca   47.12 % CaO
   Silicon   20.23 %  Si   43.27 % SiO2
   Hydrogen   0.48 %  H     4.32 % H2O
   Carbon     1.44 %  C     5.28 % CO2
   Oxygen    44.17 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca7Si6(CO3)O18•2(H2O)
Help on Environment: Environment: Rare constituent of hybrid rocks formed by the assimilation of limestone by dolerite.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1929
Help on Locality: Locality: Scawt Hill, Antrim, Ireland. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after its locality.
Help on Name Pronunciation: Name Pronunciation: Scawtite Say SCAWTITE
Help on Synonym: Synonym: ICSD 73333
  PDF 31-361

Scawtite Image

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Comments: 1 to 2 mm transparent crystals of Scawtite on dark matrix (see pink arrows in photo).
Location: Scawt Hill, Antrim, Ireland. Scale: Picture size 5 mm.
© John Veevaert

Scawtite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.6667:1:0.4362
Help on Cell Dimensions: Cell Dimensions: a = 10.121, b = 15.18, c = 6.623, Z = 2; beta = 100.55° V = 1,000.34 Den(Calc)= 2.77
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.02(1), 2.991(0.8), 3.204(0.55),

Physical Properties of Scawtite

Help on Cleavage: Cleavage: {001} Perfect, {010} Poor
Help on Color: Color: Colorless.
Help on Density: Density: 2.77
Help on Diaphaneity: Diaphaneity: Transparent
Help on Habit: Habit: Platy - Sheet forms (e.g. micas).
Help on Hardness: Hardness: 4-5 - Fluorite-Apatite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Scawtite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.023 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.023 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2199,KPDmeas= 0.2199,KC= 0.2148
Ncalc = 1.6
Help on Optical Data: Optical Data: Biaxial (+), a=1.597-1.603, b=1.606-1.609, g=1.618-1.621, bire=0.0180-0.0210, 2V(Calc)=72-84, 2V(Meas)=74-78.

Calculated Properties of Scawtite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.78 gm/cc
note: Specific Gravity of Scawtite =2.77 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEScawtite = 4.91 barns/electron
U=PEScawtite x rElectron Density= 13.65 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Scawtite is Not Radioactive

Scawtite Classification

Help on  Dana Class: Dana Class: (64)Cyclosilicates
  (64.02)3-membered rings with other anion groups
  (64.02.01)Dana Group Scawtite Ca7Si6(CO3)O18•2(H2O) C 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.CK.15 09 - SILICATES (Germanates)
  09.C - Cyclosilicates
  09.CK -[Si6O18]12- 6-membered single rings, with insular complex anions
09.CK.15 Scawtite Ca7Si6(CO3)O18•2(H2O) C 2/m 2/m

Other Scawtite Information

Help on References: References: PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)
Help on See Also: See Also: Links to other databases for Scawtite :
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.CK.15





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