Roscoelite Mineral Data

Roscoelite Mineral Data +

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General Roscoelite Information

Chemical Formula:

K(V,Al,Mg)2AlSi3O10(OH)2

Composition:

Molecular Weight = 411.01 gm

Potassium 9.51 % K 11.46 % K₂O

Magnesium 2.37 % Mg 3.92 % MgO

Aluminum 10.50 % Al 19.85 % Al₂O₃

Vanadium 9.92 % V 17.70 % V₂O₅

Silicon 20.50 % Si 43.86 % SiO₂

Hydrogen 0.49 % H 4.38 % H₂O

Oxygen 46.71 % O

______ ______

100.00 % 101.17 % = TOTAL OXIDE

Empirical Formula:

KV⁵⁺_0.8Al_0.6Mg_0.4AlSi₃O₁₀(OH)₂

Environment:

An early stage gangue material in low-temperature epithermal Au-Ag-Te deposits and from the oxidized portions of sedimentary U-V ores.

IMA Status:

Valid Species (Pre-IMA) 1876

Locality:

Stuckslacker mine, 2 miles SW of Coloma, El Dorado Co., California. Link to MinDat.org Location Data.

Name Origin:

Named for Henry Enfield Roscoe (1833-1915) of Manchester, England who first prepared pure vanadium.

Roscoelite Image

Images:

Roscoelite

Comments: Dull olive green fine grained roscoelite cementing sandstone.
Location: Rifle Mine, Garfield County, Colorado, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Roscoelite Crystallography

Axial Ratios:

a:b:c =0.5786:1:1.1276

Cell Dimensions:

a = 5.26, b = 9.09, c = 10.25, Z = 2; beta = 101° V = 481.08 Den(Calc)= 2.84

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 10(1), 3.35(0.8), 4.54(0.8),

Physical Properties of Roscoelite

Cleavage:

[001] Perfect

Color:

Brown green, Greenish brown, Yellow green, Dark brown, Dark green.

Density:

2.97

Diaphaniety:

Translucent

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Micaceous - Platy texture with "flexible" plates.

Habit:

Scaly - Morphology like fish scales.

Hardness:

2.5 - Finger Nail

Luminescence:

Non-fluorescent.

Luster:

Pearly

Streak:

greenish white

Optical Properties of Roscoelite

Gladstone-Dale:

CI meas= 0.089 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.047 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2265,KPDmeas= 0.2166,KC= 0.2377

Optical Data:

Biaxial (-), a=1.59-1.61, b=1.63-1.685, g=1.64-1.704, bire=0.0500-0.0940

Pleochroism (x):

green brown.

Pleochroism (y):

olive green.

Pleochroism (z):

olive green.

Calculated Properties of Roscoelite

Electron Density:

r_electron=2.81 gm/cc
note: r_Roscoelite=2.84 gm/cc.

Fermion Index

Fermion Index = 0.01242
Boson Index = 0.98758

Photoelectric:

PE_Roscoelite= 3.96 barns/electron
U=PE_Roscoelite x r_electron= 11.10 barns/cc.

Radioactivity:

GRapi = 135.57 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Roscoelite - barely detectable

Roscoelite Classification

Dana Class:

71.2.2a.4 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.2)with 2:1 Layers

(71.2.2a)Mica Group (Muscovite subgroup)

71.2.2a.1 Muscovite KAl2(Si3Al)O10(OH,F)2 C 2/m 2/m

71.2.2a.2 Paragonite NaAl2(Si3Al)O10(OH)2 C 2/c,Cc Mono

71.2.2a.3 Chernykhite (Ba,Na)V,Al)2(Si,Al)4O10(OH)2 C 2/c 2/m

71.2.2a.4 Roscoelite K(V,Al,Mg)2AlSi3O10(OH)2 C 2/m 2/m

71.2.2a.5 Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2 C 2/m 2/m

71.2.2a.6 Celadonite K(Mg,Fe)(Fe,Al)[Si4O10](OH)2 C 2/m 2/m

71.2.2a.6b Ferroceladonite! K2FeFeSi8O20(OH)4 C 2/m 2/m

71.2.2a.6c Ferro-aluminoceladonite! K2Fe2Al2Si8O20(OH)4 C 2/m 2/m

71.2.2a.6d Aluminoceladonite! KAl(Mg,Fe)[]Si4O10(OH)2 2/m

71.2.2a.6e Chromceladonite! KCrMg(Si4O10)(OH)2 C 2 2

71.2.2a.7 Tobelite (NH4,K)Al2(Si3Al)O10(OH)2 C 2/m 2/m

71.2.2a.8 Nanpingite Cs(Al,Mg,Fe,Li)2(Si3Al)O10(OH,F)2 C 2/c 2/m

71.2.2a.9 Boromuscovite KAl2(Si3B)O10(OH,F)2 C 2/m 2/m

71.2.2a.10 Montdorite (K,Na)(Fe,Mn,Mg)2.5[Si4O10](F,OH)2 C 2/c 2/m

71.2.2a.11 Chromphyllite! (K,Ba)(Cr,Al)2[AlSi3O10](OH,F)2 C 2c 2/m

71.2.2a.12 Shirokshinite! K(NaMg2)Si4O10F2 C 2/m 2/m

Strunz Class:

VIII/H.10-90 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica like layered silicates with [Si4O10]4- and related groups

VIII/H.10 - Mica group, Muscovite series

VIII/H.10-10 Aluminoceladonite! KAl(Mg,Fe)[]Si4O10(OH)2 2/m

VIII/H.10-20 Ferro-aluminoceladonite! K2Fe2Al2Si8O20(OH)4 C 2/m 2/m

VIII/H.10-30 Celadonite K(Mg,Fe)(Fe,Al)[Si4O10](OH)2 C 2/m 2/m

VIII/H.10-35 Chromceladonite! KCrMg(Si4O10)(OH)2 C 2 2

VIII/H.10-40 Ferroceladonite! K2FeFeSi8O20(OH)4 C 2/m 2/m

VIII/H.10-50 Paragonite NaAl2(Si3Al)O10(OH)2 C 2/c,Cc Mono

VIII/H.10-60 Boromuscovite KAl2(Si3B)O10(OH,F)2 C 2/m 2/m

VIII/H.10-70 Muscovite KAl2(Si3Al)O10(OH,F)2 C 2/m 2/m

VIII/H.10-80 Chromphyllite! (K,Ba)(Cr,Al)2[AlSi3O10](OH,F)2 C 2c 2/m

VIII/H.10-90 Roscoelite K(V,Al,Mg)2AlSi3O10(OH)2 C 2/m 2/m

VIII/H.10-95 Ganterite! [Ba0.5(Na,K)0.5]Al2(Si2.5Al1.5O10)(OH)2 C 2/c 2/m

VIII/H.10-100 Tobelite (NH4,K)Al2(Si3Al)O10(OH)2 C 2/m 2/m

VIII/H.10-110 Nanpingite Cs(Al,Mg,Fe,Li)2(Si3Al)O10(OH,F)2 C 2/c 2/m

Other Roscoelite Information

References:

NAME( MinRec) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic2)

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Roscoelite

K(V,Al,Mg)2AlSi3O10(OH)2
Dana No: 71.2.2a.4 Strunz No: VIII/H.10-90
Locality:

Notes: