Delhayelite Mineral Data
General Delhayelite Information
Chemical Formula:
(Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O)
Composition:
Molecular Weight = 3,231.17 gm
Potassium 3.03 % K 3.64 % K2 O
Sodium 5.34 % Na 7.19 % Na2 O
Calcium 6.20 % Ca 8.68 % CaO
Aluminum 5.01 % Al 9.47 % Al2 O3
Silicon 27.81 % Si 59.50 % SiO2
Hydrogen 1.12 % H 10.04 % H2 O
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
Empirical Formula:
Na7.5 K2.5 Ca5 Al6 Si32 O80 Cl0.7 F0.7 (SO4 )0.6 �18(H2 O)
Environment:
In a kalsilite-bearing melitlite-nepheline lava.
IMA Status:
Approved IMA 1959
Locality:
On Mt. Sharheru, the extinct southern cone of Mt. Nyiragongo, Kivu Province, Zaire. Link to MinDat.org Location Data.
Name Origin:
Named for Fernard Delhaye (1880-1946), Belgian geologist, a pioneer in the geological exploration of the northern Kivu region of Zaire.
Name Pronunciation:
Delhayelite + Pronunciation
Synonym:
ICSD 24616
PDF 12-286
Delhayelite Image
Images:
Delhayelite
Comments: Gray to creamy delhayelite crystal in matrix.
Location: Mt. Rasvumchorr, Chibiny, Kola, Russia.
Scale: Specimen Size 2.5x5 cm.
© Diederik Visser
Delhayelite Crystallography
Axial Ratios:
a:b:c =0.5298:1:0.2855
Cell Dimensions:
a = 13.06, b = 24.65, c = 7.04, Z = 1; V = 2,266.38 Den(Calc)= 2.37
Crystal System:
Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pnmm
X Ray Diffraction:
By Intensity(I/Io ): 3.078(1), 12.3(0.35), 6.158(0.25),
Physical Properties of Delhayelite
Cleavage:
{010} Distinct
Color:
Colorless, Greenish gray, Light gray green.
Density:
2.6
Diaphaneity:
Transparent
Habit:
Platy - Sheet forms (e.g. micas).
Hardness:
4-5 - Fluorite-Apatite
Streak:
white
Optical Properties of Delhayelite
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
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
Electron Density:
Bulk Density (Electron Density)=2.38 gm/cc note: Specific Gravity of Delhayelite =2.37 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PEDelhayelite = 2.46 barns/electronU=PEDelhayelite x r electron = 5.85 barns/cc.
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
Dana Class:
72.05.01.04 (72) Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
(72.05) with corrugated and complex layers
(72.05.01) Rhodesite group
72.05.01.01 Rhodesite KHCa2Si8O19•5(H2O) Pmam 2/m 2/m 2/m
72.05.01.02 Monteregianite-(Y) (Na,K)6(Y,Ca)2Si16O38•10(H2O) P 21 /m 2/m
72.05.01.03 Macdonaldite BaCa4[Si16O36(OH)2]•10(H2O) C mcm 2/m 2/m 2/m
72.05.01.04 Delhayelite (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O) Pnmm 2/m 2/m 2/m
72.05.01.05 Hydrodelhayelite KCa2AlSi7O17(OH)2•6(H2O) Pnm21 mm2
72.05.01.06 Seidite-(Ce) ! Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4•5(H2O) C/2c 2/m
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
References:
NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic2)
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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Print or Cut-and-Paste your Delhayelite Specimen Label here :
Delhayelite
(Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O)
Dana No: 72.05.01.04 Strunz No: 09.EB.10
Locality:
Notes:
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