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Rectorite Mineral Data
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General Rectorite Information
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Chemical Formula: |
(Na,Ca)Al4(Si,Al)8O20(OH)4•2(H2O) |
Composition: |
Molecular Weight = 784.18 gm |
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Potassium 0.50 % K 0.60 % K2O |
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Sodium 1.76 % Na 2.37 % Na2O |
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Calcium 1.53 % Ca 2.15 % CaO |
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Aluminum 20.64 % Al 39.01 % Al2O3 |
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Silicon 21.49 % Si 45.97 % SiO2 |
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Hydrogen 1.03 % H 9.19 % H2O |
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Oxygen 53.05 % O |
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______ ______ |
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100.00 % 99.29 % = TOTAL OXIDE |
Empirical Formula: |
Na0.6Ca0.3K0.1Al6Si6O20(OH)4•2(H2O) |
Environment: |
Alteration of potassic feldspars or diagenesis of muscovite. |
IMA Status: |
Valid Species (Pre-IMA) 1891 |
Locality: |
Blue Mountain district, Marble, Garland County, Arkansas, USA. Link to MinDat.org Location Data. |
Name Origin: |
Named for E. W. Rector (1849-1917), legislator and lawyer of Hot Springs, Arkansas, USA. |
Name Pronunciation: |
Rectorite + Pronunciation |
Synonym: |
Ca-Rectorite |
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K-Rectorite |
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Na-Rectorite |
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Smectite |
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Tarasovite |
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Rectorite Image |
Images:
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Rectorite
Comments: Blue Mountain District, Marble Township, Garland Co., Arkansas, USA.
Location: Five pieces of leather-like fragments of rectorite in twisted, irregular shapes.
Scale: Specimen size 1-4 cm.
© John Betts - Fine Minerals |
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Rectorite Crystallography
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Axial Ratios: |
a:b:c =0.5777:1:2.6858 |
Cell Dimensions: |
a = 5.13, b = 8.88, c = 23.85, Z = 2; beta = 96.3° V = 1,079.91 Den(Calc)= 2.41 |
Crystal System: |
Monoclinic Space Group: Unk |
X Ray Diffraction: |
By Intensity(I/Io): 4.45(1), 2.55(0.7), 1.492(0.4),12.2(0.4), 3.15(0.3), 4.99(0.3), 26.4(0.3), 2.44(0.1), |
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Physical Properties of Rectorite
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Cleavage: |
{001} Perfect |
Color: |
Yellowish white, White. |
Fracture: |
Flexible - Flexible fragments. |
Habit: |
Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite). |
Hardness: |
1-2 - Between Talc and Gypsum |
Luster: |
Earthy (Dull) |
Streak: |
white |
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Optical Properties of Rectorite
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Gladstone-Dale: |
CI calc= -0.034 (Excellent) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2252,KC= 0.2178 Ncalc = 1.52 |
Optical Data: |
Biaxial (-), a=1.519, b=1.55, g=1.559, bire=0.0400, 2V(Calc)=54, 2V(Meas)=5-20. Dispersion r > v. |
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Calculated Properties of Rectorite
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Electron Density: |
Bulk Density (Electron Density)=2.41 gm/cc note: Specific Gravity of Rectorite =2.41 gm/cc. |
Fermion Index: |
Fermion Index = 0.01 Boson Index = 0.99 |
Photoelectric: |
PERectorite = 1.72 barns/electron U=PERectorite x relectron= 4.14 barns/cc. |
Radioactivity: |
GRapi = 7.20 (Gamma Ray American Petroleum Institute Units)
Concentration of Rectorite per GRapi unit = 13.89 (%)
Estimated Radioactivity from Rectorite - barely detectable
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Rectorite Classification
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Dana Class: |
71.04.02.07 (71)Phyllosilicate Sheets of Six-Membered Rings |
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(71.04)interlayered 1:1, 2:1, and octahedra |
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(71.04.02)Interstratified Chlorite-Smectite group |
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71.04.02.01 Dozyite (Mg7Al2)(Si4Al2)O15(OH)12 Cm m |
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71.04.02.02 Lunijianlaite LiAl6(Si7Al)O20(OH)10 Unk Mono |
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71.04.02.03 Saliotite Na0.5Li0.5Al3AlSi3O10(OH)5 C 2/m 2/m |
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71.04.02.04 Tosudite Na0,5(Al,Mg)6(Si,Al)8O18(OH)12•5(H2O) Unk Ortho |
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71.04.02.05 Corrensite (Ca,Na,K)(Mg,Fe,Al)9(Si,Al)8O20(OH)10•n(H2O) Unk Ortho |
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71.04.02.06 Kulkeite Na0.35Mg8AlSi7O20(OH)10 Unk Mono |
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71.04.02.07 Rectorite (Na,Ca)Al4(Si,Al)8O20(OH)4•2(H2O) Unk Mono |
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71.04.02.08 Aliettite [Mg3Si4O10(OH)2](Ca0.5,Na)0.33(Al,Mg,Fe)2-3(Si,Al)4O10(OH)2•n(H2O) Unk Mono |
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71.04.02.09 Glagolevite! NaMg6[Si3AlO10](OH,O)8•H2O C1 1 |
Strunz Class: |
09.EC.60 09 - SILICATES (Germanates) |
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09.E - Phyllosilicates |
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09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets |
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09.EC.60 Aliettite [Mg3Si4O10(OH)2](Ca0.5,Na)0.33(Al,Mg,Fe)2-3(Si,Al)4O10(OH)2•n(H2O) Unk Mono |
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09.EC.60 Dozyite (Mg7Al2)(Si4Al2)O15(OH)12 Cm m |
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09.EC.60 Corrensite (Ca,Na,K)(Mg,Fe,Al)9(Si,Al)8O20(OH)10•n(H2O) Unk Ortho |
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09.EC.60 Kulkeite Na0.35Mg8AlSi7O20(OH)10 Unk Mono |
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09.EC.60 Karpinskite (Mg,Ni)2Si2O5(OH)2(?) Unk Mono |
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09.EC.60 Illite* (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/m 2/m |
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09.EC.60 Hydrobiotite [K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2]•[(Mg,Fe,Al)3(Si,Al)4O10(OH)2•4(H2O)] C 2/m 2/m |
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09.EC.60 Lunijianlaite LiAl6(Si7Al)O20(OH)10 Unk Mono |
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09.EC.60 Rectorite (Na,Ca)Al4(Si,Al)8O20(OH)4•2(H2O) Unk Mono |
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09.EC.60 Saliotite Na0.5Li0.5Al3AlSi3O10(OH)5 C 2/m 2/m |
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09.EC.60 Tosudite Na0,5(Al,Mg)6(Si,Al)8O18(OH)12•5(H2O) Unk Ortho |
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09.EC.60 Brinrobertsite! (Na,K,Ca)x(Al,Fe,Mg)4(Si,Al)8O20(OH)4•3.54(H2O)[x=0.35,n=3.54] pseudo 2/m 2/m |
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Other Rectorite Information
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References: |
NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8) |
See Also: |
Links to other databases for Rectorite :
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 Rectorite Specimen Label here :
Rectorite
(Na,Ca)Al4(Si,Al)8O20(OH)4•2(H2O)
Dana No: 71.04.02.07 Strunz No: 09.EC.60
Locality:
Notes:
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