Tobelite Mineral Data

Tobelite Mineral Data +

General Tobelite Information

Chemical Formula:

(NH4,K)Al2(Si3Al)O10(OH)2

Composition:

Molecular Weight = 376.27 gm

Potassium 2.08 % K 2.50 % K₂O

Aluminum 20.08 % Al 37.94 % Al₂O₃

Silicon 23.89 % Si 51.10 % SiO₂

Hydrogen 0.54 % H - % Calc as (NH₄)₂O

Hydrogen 0.54 % H 4.79 % H₂O

Nitrogen 1.86 % N 3.46 % (NH₄)₂O

Oxygen 51.03 % O

______ ______

100.00 % 99.79 % = TOTAL OXIDE

Empirical Formula:

(NH₄)_0.5K_0.2Al₂Si_3.2Al_0.8O₁₀(OH)₂

Environment:

Hydrothemal alteration of biotite andesite dike or in a hydrothermally altered rhyolite tuff.

IMA Status:

Approved IMA 1982

Locality:

Ohgidani pottery stone deposit, Tobe, Ehime Prefecture, adn in the Horo pryophyllite deposit, Toyosaka, hiroshima Prefecture, Japan. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Tobelite Image

Images:

Tobelite

Comments: Fine grained massive tobelite.
Location: Tobe, Ehime, Japan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Tobelite Crystallography

Axial Ratios:

a:b:c =0.5807:1:1.1625

Cell Dimensions:

a = 5.219, b = 8.986, c = 10.447, Z = 2; beta = 101.31° V = 480.43 Den(Calc)= 2.60

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): 10.24(1), 3.408(0.6), 2.566(0.45),

Physical Properties of Tobelite

Cleavage:

[001] Perfect

Color:

Yellowish green, Pearly white.

Density:

2.58

Diaphaniety:

Transparent

Habit:

Massive - Fibrous - Distinctly fibrous fine-grained forms.

Habit:

Scaly - Morphology like fish scales.

Hardness:

2 - Gypsum

Luster:

Vitreous - Silky

Streak:

white

Optical Properties of Tobelite

Gladstone-Dale:

CI meas= -0.083 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.074 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2213,KPDmeas= 0.2231,KC= 0.206

Optical Data:

Biaxial (-), a=1.555-1.56, b=1.575-1.587, g=1.581-1.595, bire=0.0260-0.0350, 2V(Calc)=56, 2V(Meas)=28-30.

Calculated Properties of Tobelite

Electron Density:

r_electron=2.61 gm/cc
note: r_Tobelite=2.60 gm/cc.

Fermion Index

Fermion Index = 0.02994
Boson Index = 0.97006

Photoelectric:

PE_Tobelite= 1.72 barns/electron
U=PE_Tobelite x r_electron= 4.49 barns/cc.

Radioactivity:

GRapi = 30.06 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Tobelite - barely detectable

Tobelite Classification

Dana Class:

71.2.2a.7 (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.10-100 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 Tobelite Information

References:

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

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Print or Cut-and-Paste your Tobelite Specimen Label here :

Tobelite

(NH4,K)Al2(Si3Al)O10(OH)2
Dana No: 71.2.2a.7 Strunz No: VIII/H.10-100
Locality:

Notes: