Rhodesite Mineral Data
General Rhodesite Information
Chemical Formula:
KHCa2Si8O19•5(H2O)
Composition:
Molecular Weight = 732.57 gm
Potassium 3.20 % K 3.86 % K2 O
Sodium 1.26 % Na 1.69 % Na2 O
Calcium 10.94 % Ca 15.31 % CaO
Silicon 30.67 % Si 65.62 % SiO2
Hydrogen 1.51 % H 13.53 % H2 O
Oxygen 52.42 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
K0.6 Na0.4 HCa2 Si8 O19 •5(H2 O)
Environment:
In a kimberlite pipe and also in altered silicic lavas.
IMA Status:
Valid Species (Pre-IMA) 1957
Locality:
Bultfontein diamond mine, Kimberley, Cape Province, South Africa. Link to MinDat.org Location Data.
Name Origin:
Named for Cecil John Rhodes (1853-1902), British founder of the DeBeers Mining Company and for Rhodes University, Grahamstown, South Africa where the mineral was studied.
Name Pronunciation:
Rhodesite + Pronunciation
Synonym:
ICSD 36551
PDF 22-1253
Rhodesite Image
Images:
Images:
Rhodesite Crystallography
Axial Ratios:
a:b:c =3.5722:1:1.0755
Cell Dimensions:
a = 23.416, b = 6.555, c = 7.05, Z = 2; V = 1,082.12 Den(Calc)= 2.25
Crystal System:
Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pmam
X Ray Diffraction:
By Intensity(I/Io ): 6.55(1), 4.39(0.45), 5.9(0.35),
Physical Properties of Rhodesite
Cleavage:
{100} Good
Color:
Silky white.
Density:
2.36
Diaphaneity:
Translucent to transparent
Habit:
Fibrous - Crystals made up of fibers.
Hardness:
3-4 - Calcite-Fluorite
Luster:
Silky
Streak:
white
Optical Properties of Rhodesite
Gladstone-Dale:
CI meas = 0.044 (Good) - where the CI = (1-KPDmeas /KC ) CI calc = -0.002 (Superior) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2259,KPDmeas = 0.2154,KC = 0.2254 Ncalc = 1.51 - 1.53
Optical Data:
Biaxial (+), a=1.501-1.504, b=1.506-1.508, g=1.513-1.518, bire=0.0120-0.0140
Calculated Properties of Rhodesite
Electron Density:
Bulk Density (Electron Density)=2.28 gm/cc note: Specific Gravity of Rhodesite =2.25 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PERhodesite = 2.87 barns/electronU=PERhodesite x r electron = 6.53 barns/cc.
Radioactivity:
GRapi = 46.76 (Gamma Ray American Petroleum Institute Units)
Concentration of Rhodesite per GRapi unit = 2.14 (%)
Estimated Radioactivity from Rhodesite - barely detectable
Rhodesite Classification
Dana Class:
72.05.01.01 (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.05 09 - SILICATES (Germanates)
09.E - Phyllosilicates
09.EB -Double nets with 4- and 6-membered rings
09.EB.05 Macdonaldite BaCa4[Si16O36(OH)2]•10(H2O) C mcm 2/m 2/m 2/m
09.EB.05 Rhodesite KHCa2Si8O19•5(H2O) Pmam 2/m 2/m 2/m
Other Rhodesite Information
References:
NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic2)
See Also:
Links to other databases for Rhodesite :
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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Rhodesite
KHCa2Si8O19•5(H2O)
Dana No: 72.05.01.01 Strunz No: 09.EB.05
Locality:
Notes:
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