Mineralogy Database

Tilleyite Mineral Data

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General Tilleyite Information

Help on Chemical  Formula: Chemical Formula: Ca5Si2O7(CO3)2
Help on Composition: Composition: Molecular Weight = 488.58 gm
   Calcium  41.02 %  Ca   57.39 % CaO
   Silicon  11.50 %  Si   24.60 % SiO2
   Carbon    4.92 %  C    18.02 % CO2
   Oxygen   42.57 %  O
           ______        ______ 
           100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca5Si2O7(CO3)2
Help on Environment: Environment: In the contact metamorphic zone between igneous rocks and limestones, formed at low pressure and high temperature.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1933
Help on Locality: Locality: Crestmore quarry, 5 miles NW of Riverside, Riverside County, California. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Cecil Edgar Tilley (1894-1973), British petrologist, Cambridge University, Cambridge, England.
Help on Name Pronunciation: Name Pronunciation: Tilleyite + Pronunciation Say TILLEYITE
Help on Synonym: Synonym: ICSD 14256
  PDF 24-184

Tilleyite Image

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Comments: Opaque white fibrous tilleyite with blue calcite.
Location: Crestmore Quarry, Riverside County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Tilleyite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.4631:1:0.7428
Help on Cell Dimensions: Cell Dimensions: a = 15.025, b = 10.269, c = 7.628, Z = 4; beta = 105.833° V = 1,132.29 Den(Calc)= 2.87
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): 3.005(1), 3.095(0.85), 2.895(0.65),

Physical Properties of Tilleyite

Help on Cleavage: Cleavage: {100} Perfect, {101} Good
Help on Color: Color: Colorless, White.
Help on Density: Density: 2.84
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Streak: Streak: white

Optical Properties of Tilleyite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.064 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= -0.053 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2208,KPDmeas= 0.2231,KC= 0.2097
Ncalc = 1.6
Help on Optical Data: Optical Data: Biaxial (+), a=1.612-1.617, b=1.632-1.635, g=1.652-1.654, bire=0.0370-0.0400, 2V(Calc)=88-90, 2V(Meas)=85-90. Dispersion r < v.

Calculated Properties of Tilleyite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.87 gm/cc
note: Specific Gravity of Tilleyite =2.87 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0066679407
Boson Index = 0.9933320593
Help on Photoelectric: Photoelectric: PETilleyite = 5.53 barns/electron
U=PETilleyite x rElectron Density= 15.84 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tilleyite is Not Radioactive

Tilleyite Classification

Help on  Dana Class: Dana Class: (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O
  (56.02)with cations in [4] and/or >[4] coordination
  (56.02.09)Tilleyite - Killalaite group Tilleyite Ca5Si2O7(CO3)2 P 21/a 2/m Killalaite 2Ca3Si2O7•(H2O) P 21/m 2/m Foshallasite? Ca3Si2O7•3(H2O) Mono
Help on  Strunz Class: Strunz Class: 09.BE.08.2 09 - SILICATES (Germanates)
  09.B - Sorosilicates
  09.BE -Si2O7 groups with additional anions;
09.BE.08.2 Tilleyite Ca5Si2O7(CO3)2 P 21/a 2/m

Other Tilleyite 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 Tilleyite :
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.BE.08.2





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