Mineralogy Database

Bredigite Mineral Data

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General Bredigite Information

Help on Chemical  Formula: Chemical Formula: Ca7Mg(SiO4)4
Help on Composition: Composition: Molecular Weight = 673.18 gm
   Calcium    41.67 %  Ca   58.31 % CaO
   Magnesium   3.61 %  Mg    5.99 % MgO
   Silicon    16.69 %  Si   35.70 % SiO2
   Oxygen     38.03 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca7Mg(SiO4)4
Help on Environment: Environment: In contact metamophosed limestones and dolostones intruded by diabase.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1948
Help on Locality: Locality: In the USA, at Marble Canyon, Culberson Co., Texas. In Ireland, at Scawt Hill and Ballycraigy, near Larne, Co. Antrim. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: For Max Albrecht Bredig (1902- ), physical chemist, who studied the polymorphism of Ca2SiO4.
Help on Name Pronunciation: Name Pronunciation: Bredigite + Pronunciation Say BREDIGITE
Help on Synonym: Synonym: ICSD 9828
  PDF 36-399

Bredigite Image

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

Comments: White veins of bredigite in massive gray spurrite (slabbed specimen).
Location: Camphouse, Ardnamurchan, Argyll, Highland, Scotland. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Bredigite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.5948:1:0.3674
Help on Cell Dimensions: Cell Dimensions: a = 10.909, b = 18.34, c = 6.739, Z = 4; V = 1,348.28 Den(Calc)= 3.32
Help on Crystal System: Crystal System: Orthorhombic - Pyramidal H-M Symbol (mm2) Space Group: P 2nn
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.663(1), 2.73(1), 2.259(0.8),

Physical Properties of Bredigite

Help on Cleavage: Cleavage: {130} Distinct
Help on Color: Color: Colorless, Gray.
Help on Density: Density: 3.4
Help on Diaphaneity: Diaphaneity: Transparent
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Bredigite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.011 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.036 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2162,KPDmeas= 0.2111,KC= 0.2087
Ncalc = 1.69 - 1.71
Help on Optical Data: Optical Data: Biaxial (+), a=1.712, b=1.716, g=1.725, bire=0.0130, 2V(Calc)=68, 2V(Meas)=30.

Calculated Properties of Bredigite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.39 gm/cc
note: Specific Gravity of Bredigite =3.40 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEBredigite = 5.82 barns/electron
U=PEBredigite x rElectron Density= 19.77 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Bredigite is Not Radioactive

Bredigite Classification

Help on  Dana Class: Dana Class: (51)Nesosilicate Insular SiO4 Groups Only
  (51.04)with cations in [6] and >[6] coordination
  (51.04.01)Dana Group Bredigite Ca7Mg(SiO4)4 P 2nn mm2
Help on  Strunz Class: Strunz Class: 09.AD.20 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AD -Nesosilicates without additional anions;
09.AD.20 Bredigite Ca7Mg(SiO4)4 P 2nn mm2

Other Bredigite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Bredigite :
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.AD.20





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