Mineralogy Database

Ecdemite Mineral Data

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General Ecdemite Information

Help on Chemical  Formula: Chemical Formula: Pb6As+++2O7Cl4
Help on Composition: Composition: Molecular Weight = 1,646.85 gm
   Arsenic    9.10 %  As   12.01 % As2O3
   Lead      75.49 %  Pb   81.32 % PbO
   Chlorine   8.61 %  Cl    8.61 % Cl
               -   %   Cl   -1.94 % -O=Cl2   
   Oxygen     6.80 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Pb6As2O7Cl4
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1877
Help on Locality: Locality: Langban and Harstig mines, Varmland, Sweden. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named from the Greek for "unusual", in reference to the composition.
Help on Name Pronunciation: Name Pronunciation: Ecdemite Say ECDEMITE

Ecdemite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:2.37222
Help on Cell Dimensions: Cell Dimensions: a = 10.8, c = 25.62, Z = 8; V = 2,988.32 Den(Calc)= 7.32
Help on Crystal System: Crystal System: Tetragonal Space Group: Unk
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.85(1), 2.72(0.8), 3.66(0.8),

Physical Properties of Ecdemite

Help on Cleavage: Cleavage: {001} Perfect
Help on Color: Color: Green yellow, Yellow, Orange.
Help on Density: Density: 6.9 - 7.1, Average = 7
Help on Diaphaneity: Diaphaneity: Translucent
Help on Habit: Habit: Encrustations - Forms crust-like aggregates on matrix.
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Habit: Habit: Tabular - Form dimensions are thin in one direction.
Help on Hardness: Hardness: 2.5 - Finger Nail
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Vitreous - Greasy
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: light yellow

Optical Properties of Ecdemite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.122 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.073 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1755,KPDmeas= 0.1836,KC= 0.1636
Ncalc = 2.13 - 2.2
Help on Optical Data: Optical Data: Uniaxial (-), e=2.25, w=2.32, bire=0.0700.

Calculated Properties of Ecdemite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=6.06 gm/cc
note: Specific Gravity of Ecdemite =7.32 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.16
Boson Index = 0.84
Help on Photoelectric: Photoelectric: PEEcdemite =1,406.90 barns/electron
U=PEEcdemite x rElectron Density=8,529.71 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Ecdemite is Not Radioactive

Ecdemite Classification

Help on  Dana Class: Dana Class: (46)Basic or Halogen-Containing Antimonites, Arsenites and Phosphites
  (46.02)with miscellaneous formulae
  (46.02.01)Dana Group Ecdemite Pb6As2O7Cl4 Unk Tetra
Help on  Strunz Class: Strunz Class: 03.DC.65 03 - HALIDES
  03.D - Oxyhalides, Hydroxyhalides and Related Double Halides
  03.DC -With Pb (As,Sb,Bi), without Cu
03.DC.65 Ecdemite Pb6As2O7Cl4 Unk Tetra
03.DC.65 Heliophyllite Pb6As2O7Cl4 Unk Ortho

Other Ecdemite Information

Help on References: References: NAME( Dana8) 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 Ecdemite :
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: 03.DC.65





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