General Cronstedtite Information
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Chemical Formula: |
Fe++2Fe+++(SiFe+++)O5(OH)4 |
Composition: |
Molecular Weight = 399.50 gm |
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Iron 55.92 % Fe 35.97 % FeO / 39.97 % Fe2O3 |
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Silicon 7.03 % Si 15.04 % SiO2 |
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Hydrogen 1.01 % H 9.02 % H2O |
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Oxygen 36.04 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
Fe2+2Fe3+2SiO5(OH)4 |
IMA Status: |
Valid Species (Pre-IMA) 1821 |
Locality: |
Pribram and Kuttenberg, Bohemia of Czechoslovakia. Link to MinDat.org Location Data. |
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Cronstedtite Image |
Images:
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Cronstedtite Crystallography
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Axial Ratios: |
a:c = 1:1.29329 |
Cell Dimensions: |
a = 5.486, c = 7.095, Z = 1; V = 184.92 Den(Calc)= 3.59 |
Crystal System: |
Trigonal - Ditrigonal PyramidalH-M Symbol (3m) Space Group: P 31m |
X Ray Diffraction: |
By Intensity(I/Io): 2.56(1), 7.1(0.9), 3.548(0.6), |
Crystal Structure:
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Hendricks S B , American Mineralogist , 24 (1939) p.529-539, Random structures of layer minerals as illustrated by cronstedtite, (2FeO.Fe2O3.SiO2.2H2O). Possible iron content of kaolin
View Additional jPOWD Structure files for Cronstedtite
[1]
[2]
[3]
[4]
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Physical Properties of Cronstedtite
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Cleavage: |
[001] Perfect |
Color: |
Brownish black, Greenish black, Dark brown, Black. |
Density: |
3.34 - 3.35, Average = 3.34 |
Diaphaniety: |
Transparent to translucent |
Habit: |
Amorphous - No crystalline form or imitative shape. |
Habit: |
Divergent - Crystals radiate from a center without producing stellar forms. |
Habit: |
Pyramidal - Crystals are shaped like pyramids. |
Hardness: |
3.5 - Copper Penny |
Luster: |
Vitreous - Resinous |
Streak: |
dark olive green |
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Optical Properties of Cronstedtite
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Optical Data: |
Biaxial (-), a=1.72, b=1.8, g=1.8, bire=0.0800, 2V(Calc)=0, 2V(Meas)=0. |
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Calculated Properties of Cronstedtite
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Electron Density: |
relectron=3.49 gm/cc note: rCronstedtite =3.59 gm/cc. |
Fermion Index |
Fermion Index = 0.01531 Boson Index = 0.98469 |
Photoelectric: |
PECronstedtite = 17.04 barns/electron U=PECronstedtite x relectron= 59.43 barns/cc. |
Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Cronstedtite is Not Radioactive |
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Cronstedtite Classification
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Dana Class: |
71.1.2c.7 (71)Phyllosilicate Sheets of Six-Membered Rings |
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(71.1)with 1:1 layers |
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(71.1.2c)Serpentine group (Amesite subgroup) |
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71.1.2c.1 Amesite Mg2Al(SiAl)O5(OH)4 C1 1 |
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71.1.2c.2 Berthierine (Fe,Fe,Al,Mg)2-3(Si,Al)2O5(OH)4 Cm m |
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71.1.2c.3 Brindleyite (Ni,Mg,Fe)2Al(SiAl)O5(OH)4 C 2 2 |
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71.1.2c.4 Fraipontite (Zn,Al)3(Si,Al)2O5(OH)4 Cm m |
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71.1.2c.5 Kellyite (Mn,Mg,Al)3(Si,Al)2O5(OH)4 P 63 6 |
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71.1.2c.6 Manandonite Li2Al4[(Si2AlB)O10](OH)8 C1 1 |
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71.1.2c.7 Cronstedtite Fe2Fe(SiFe)O5(OH)4 P 31m 3m |
Strunz Class: |
VIII/H.27-120 VIII - Silicates |
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VIII/H - Phyllosilicates (layered) Mica like with [Si4O10]4- and related groups |
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VIII/H.27 - Serpentine group |
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VIII/H.27-10 Antigorite (Mg,Fe)3Si2O5(OH)4 Cm m |
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VIII/H.27-20 Lizardite Mg3Si2O5(OH)4 P1 1 |
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VIII/H.27-30 Clinochrysotile Mg3Si2O5(OH)4 Cc, C 2/m Mono |
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VIII/H.27-40 Orthochrysotile Mg3Si2O5(OH)4 Unk Ortho |
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VIII/H.27-50 Parachrysotile Mg3Si2O5(OH)4 Unk Ortho |
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VIII/H.27-55 Caryopilite (Mn,Mg,Zn,Fe)3(Si,As)2O510(OH,Cl)4 Cm or C 2/m Mono |
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VIII/H.27-60 Greenalite (Fe,Fe)2-3Si2O5(OH)4 Unk Mono |
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VIII/H.27-70 Berthierine (Fe,Fe,Al,Mg)2-3(Si,Al)2O5(OH)4 Cm m |
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VIII/H.27-80 Fraipontite (Zn,Al)3(Si,Al)2O5(OH)4 Cm m |
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VIII/H.27-90 Zinalsite Zn2AlSi2O5(OH)4·2(H2O)(?) Mono |
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VIII/H.27-95 Dozyite (Mg7Al2)(Si4Al2)O15(OH)12 Cm m |
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VIII/H.27-100 Amesite Mg2Al(SiAl)O5(OH)4 C1 1 |
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VIII/H.27-110 Kellyite (Mn,Mg,Al)3(Si,Al)2O5(OH)4 P 63 6 |
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VIII/H.27-120 Cronstedtite Fe2Fe(SiFe)O5(OH)4 P 31m 3m |
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VIII/H.27-140 Karpinskite (Mg,Ni)2Si2O5(OH)2(?) Unk Mono |
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VIII/H.27-150 Nepouite Ni3Si2O5(OH)4 Ccm21 mm2 |
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VIII/H.27-160 Pecoraite Ni3Si2O5(OH)4 C 2/m 2/m |
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VIII/H.27-170 Brindleyite (Ni,Mg,Fe)2Al(SiAl)O5(OH)4 C 2 2 |
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VIII/H.27-180 Maufite (Mg,Ni)Al4Si3O13·4(H2O)(?) Mono ? Mono |
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VIII/H.27-190 Carlosturanite (Mg,Fe,Ti,Mn)21(Si,Al)12O28(OH)34 Cm m |
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Other Cronstedtite Information
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References: |
NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990) |
See Also: |
Links to other databases for Cronstedtite :
1 -Am. Min. Crystal Structure Database
2 -Athena
3 - Crocoite.com Mineral Locations
4 - EUROmin Project
5 -Google Images
6 -Google Scholar
7 -Handbook of Mineralogy (MinSocAm)
8 -Handbook of Mineralogy (UofA)
9 -MinDAT
10 -MinMax(Deutsch)
11 -MinMax(English)
12 - Mineral and Gemstone Kingdom
13 -Mineralienatlas (Deutsch)
14 -QUT Mineral Atlas
15 - WWW-MINCRYST
16 -École des Mines de Paris
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Print or Cut-and-Paste your Cronstedtite Specimen Label here :
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Cronstedtite
Fe++2Fe+++(SiFe+++)O5(OH)4
Dana No: 71.1.2c.7 Strunz No: VIII/H.27-120
Locality:
Notes:
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