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Lecontite Mineral Data

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General Lecontite Information

Help on Chemical  Formula: Chemical Formula: (NH4,K)Na(SO4)•2(H2O)
Help on Composition: Composition: Molecular Weight = 178.39 gm
   Potassium   5.48 %  K     6.60 % K2O
   Sodium     12.89 %  Na   17.37 % Na2O
   Hydrogen    1.70 %  H      -   % Calc as (NH4)2O
   Hydrogen    2.26 %  H    20.20 % H2O
   Sulfur     17.98 %  S    44.88 % SO3
   Nitrogen    5.89 %  N    10.95 % (NH4)2O
   Oxygen     53.81 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: (NH4)0.75K0.25Na(SO4)•2(H2O)
Help on Environment: Environment: Early product of the breakdown of bat guano.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1858
Help on Locality: Locality: Las Piedras Cave, near Comayagua, 62 km northwest of Tegucigalpa, Honduras. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for John Lawrence LeConte (1825-1883), American entomologist, University of California, Berkeley, California, USA, who discovered the mineral.
Help on Name Pronunciation: Name Pronunciation: Lecontite + Pronunciation Say LECONTITE
Help on Synonym: Synonym: ICSD 77896
  PDF 15-283

Lecontite Image

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  Lecontite   Mascagnite

Comments: SEM BSE image of fine-grained lecontite (Le) and thenardite, occupying the space between mascagnite (M) crystals. CanMin 47:573.
Location: Coal-waste heap in Avion, northern France, that has been undergoing subsurface combustion for several decades. Scale: See Image.
© Canadian Mineralogist

Lecontite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.6412:1:0.4856
Help on Cell Dimensions: Cell Dimensions: a = 8.24, b = 12.85, c = 6.24, Z = 4; V = 660.72 Den(Calc)= 1.79
Help on Crystal System: Crystal System: Orthorhombic - Disphenoidal H-M Symbol (2 2 2) Space Group: P 212121
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 5.068(1), 3.802(0.94), 3.033(0.89),

Physical Properties of Lecontite

Help on Cleavage: Cleavage: {011} Distinct
Help on Color: Color: Colorless.
Help on Density: Density: 1.745
Help on Diaphaneity: Diaphaneity: Transparent
Help on Hardness: Hardness: 2-2.5 - Gypsum-Finger Nail
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Lecontite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.328 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.295 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2512,KPDmeas= 0.2577,KC= 0.1941
Ncalc = 1.34 - 1.35
Help on Optical Data: Optical Data: Biaxial (-), a=1.44, b=1.454, g=1.455, bire=0.0150, 2V(Calc)=28, 2V(Meas)=29.74.

Calculated Properties of Lecontite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=1.85 gm/cc
note: Specific Gravity of Lecontite =1.79 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.06
Boson Index = 0.94
Help on Photoelectric: Photoelectric: PELecontite = 1.87 barns/electron
U=PELecontite x relectron= 3.46 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 81.53 (Gamma Ray American Petroleum Institute Units)
Concentration of Lecontite per GRapi unit = 1.23 (%)

Estimated Radioactivity from Lecontite - barely detectable


Lecontite Classification

Help on  Dana Class: Dana Class: (29)Hydrated Acid and Sulfates
  (29.02)where (A+)2 XO4 � x(H2O)
  (29.02.01)Dana Group Lecontite (NH4,K)Na(SO4)•2(H2O) P 212121 2 2 2
Help on  Strunz Class: Strunz Class: 07.CD.15 07 - SULFATES (SELENATES, TELLURATES)
  07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O
  07.CD -With only large cations
07.CD.15 Lecontite (NH4,K)Na(SO4)•2(H2O) P 212121 2 2 2

Other Lecontite Information

Help on References: References: NAME( AntBidBlaNic5) 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 Lecontite :
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: 07.CD.15





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