Mineralogy Database

Delhayelite Mineral Data

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General Delhayelite Information

Help on Chemical  Formula: Chemical Formula: (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O)
Help on Composition: Composition: Molecular Weight = 3,231.17 gm
   Potassium   3.03 %  K     3.64 % K2O
   Sodium      5.34 %  Na    7.19 % Na2O
   Calcium     6.20 %  Ca    8.68 % CaO
   Aluminum    5.01 %  Al    9.47 % Al2O3
   Silicon    27.81 %  Si   59.50 % SiO2
   Hydrogen    1.12 %  H    10.04 % H2O
   Sulfur      0.60 %  S     1.49 % SO3
   Chlorine    0.77 %  Cl    0.77 % Cl
                -   %   Cl   -0.17 % -O=Cl2   
   Oxygen     49.71 %  O
   Fluorine    0.41 %  F     0.41 % F
                -   %   F    -0.17 % -O=F2    
             ______        ______ 
             100.00 %      100.84 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na7.5K2.5Ca5Al6Si32O80Cl0.7F0.7(SO4)0.6´┐Ż18(H2O)
Help on Environment: Environment: In a kalsilite-bearing melitlite-nepheline lava.
Help on IMA Status: IMA Status: Approved IMA 1959
Help on Locality: Locality: On Mt. Sharheru, the extinct southern cone of Mt. Nyiragongo, Kivu Province, Zaire. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Fernard Delhaye (1880-1946), Belgian geologist, a pioneer in the geological exploration of the northern Kivu region of Zaire.
Help on Name Pronunciation: Name Pronunciation: Delhayelite + Pronunciation Say DELHAYELITE
Help on Synonym: Synonym: ICSD 24616
  PDF 12-286

Delhayelite Image

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Comments: Gray to creamy delhayelite crystal in matrix.
Location: Mt. Rasvumchorr, Chibiny, Kola, Russia. Scale: Specimen Size 2.5x5 cm.
© Diederik Visser

Delhayelite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.5298:1:0.2855
Help on Cell Dimensions: Cell Dimensions: a = 13.06, b = 24.65, c = 7.04, Z = 1; V = 2,266.38 Den(Calc)= 2.37
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pnmm
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.078(1), 12.3(0.35), 6.158(0.25),

Physical Properties of Delhayelite

Help on Cleavage: Cleavage: {010} Distinct
Help on Color: Color: Colorless, Greenish gray, Light gray green.
Help on Density: Density: 2.6
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 Streak: Streak: white

Optical Properties of Delhayelite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.077 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= -0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2245,KPDmeas= 0.2046,KC= 0.2218
Ncalc = 1.53 - 1.58
Help on Optical Data: Optical Data: Biaxial (-), a=1.532, b=1.532, g=1.532, bire=0.0000, 2V(Calc)=0, 2V(Meas)=83.

Calculated Properties of Delhayelite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.38 gm/cc
note: Specific Gravity of Delhayelite =2.37 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEDelhayelite = 2.46 barns/electron
U=PEDelhayelite x relectron= 5.85 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 43.87 (Gamma Ray American Petroleum Institute Units)
Concentration of Delhayelite per GRapi unit = 2.28 (%)

Estimated Radioactivity from Delhayelite - barely detectable


Delhayelite Classification

Help on  Dana Class: Dana Class: (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
  (72.05)with corrugated and complex layers
  (72.05.01)Rhodesite group Rhodesite KHCa2Si8O19•5(H2O) Pmam 2/m 2/m 2/m Monteregianite-(Y) (Na,K)6(Y,Ca)2Si16O38•10(H2O) P 21/m 2/m Macdonaldite BaCa4[Si16O36(OH)2]•10(H2O) C mcm 2/m 2/m 2/m Delhayelite (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O) Pnmm 2/m 2/m 2/m Hydrodelhayelite KCa2AlSi7O17(OH)2•6(H2O) Pnm21 mm2 Seidite-(Ce)! Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4•5(H2O) C/2c 2/m
Help on  Strunz Class: Strunz Class: 09.EB.10 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.EB -Double nets with 4- and 6-membered rings
09.EB.10 Delhayelite (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O) Pnmm 2/m 2/m 2/m
09.EB.10 Hydrodelhayelite KCa2AlSi7O17(OH)2•6(H2O) Pnm21 mm2

Other Delhayelite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic2)
Help on See Also: See Also: Links to other databases for Delhayelite :
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.EB.10





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