Hydrobiotite Mineral Data

Hydrobiotite Mineral Data +

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General Hydrobiotite Information

Chemical Formula:

[K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2]·[(Mg,Fe++,Al)3(Si,Al)4O10(OH)2·4(H2O)]

Composition:

Molecular Weight = 464.62 gm

Potassium 2.52 % K 3.04 % K₂O

Calcium 0.86 % Ca 1.21 % CaO

Magnesium 12.03 % Mg 19.95 % MgO

Aluminum 6.97 % Al 13.17 % Al₂O₃

Iron 7.21 % Fe 10.31 % Fe₂O₃

Silicon 16.93 % Si 36.21 % SiO₂

Hydrogen 1.69 % H 15.12 % H₂O

Oxygen 50.96 % O

Fluorine 0.82 % F 0.82 % F

- % F -0.34 % -O=F₂

______ ______

100.00 % 99.48 % = TOTAL OXIDE

Empirical Formula:

Mg_2.3Fe³⁺_0.6K_0.3Ca_0.1Si_2.8Al_1.2O₁₀(OH)_1.8F_0.2·3(H₂O)

Environment:

Found in a wide variety of sedimentary environments.

IMA Status:

Valid Species (Pre-IMA) 1882

Locality:

Common world wide. Link to MinDat.org Location Data.

Name Origin:

Named for the water content and its relationship to biotite.

Synonym:

Biotitic vermiculite

Hydromica

Jefferisite

Hydrobiotite Image

Images:

Hydrobiotite

Comments: Silvery brown micaceous hydrobiotite.
Location: Oaxaca, Mexico. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Hydrobiotite Crystallography

Axial Ratios:

a:b:c =0.5777:1:2.7222

Cell Dimensions:

a = 5.2, b = 9, c = 24.5, Z = 4; beta = 90° V = 1,146.60 Den(Calc)= 2.69

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): 12.26(1), 3.5(0.5), 3.05(0.2),23.6(0.2), 2.04(0.15), 4.88(0.15), 2.73(0.1), 8.18(0.05),

Physical Properties of Hydrobiotite

Cleavage:

[001] Perfect

Color:

Golden yellow, Black.

Density:

2.49 - 2.64, Average = 2.56

Diaphaniety:

Translucent

Fracture:

Flexible - Flexible fragments.

Hardness:

2.5-3 - Finger Nail-Calcite

Luster:

Sub Metallic

Streak:

white

Optical Properties of Hydrobiotite

Gladstone-Dale:

CI meas= 0.066 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.11 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2095,KPDmeas= 0.2197,KC= 0.2353

Optical Data:

Biaxial (-), b=1.56-1.562, g=1.565-1.567, , 2V(Meas)=10.

Pleochroism (x):

light brown.

Pleochroism (y):

brown.

Pleochroism (z):

brown.

Calculated Properties of Hydrobiotite

Electron Density:

r_electron=2.58 gm/cc
note: r_Hydrobiotite=2.57 gm/cc.

Fermion Index

Fermion Index = 0.02172
Boson Index = 0.97828

Photoelectric:

PE_Hydrobiotite= 3.61 barns/electron
U=PE_Hydrobiotite x r_electron= 9.31 barns/cc.

Radioactivity:

GRapi = 36.65 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Hydrobiotite - barely detectable

Hydrobiotite Classification

Dana Class:

71.2.2d.1 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.2)with 2:1 Layers

(71.2.2d)Mica Group (Hydromica subgroup)

71.2.2d.1 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

71.2.2d.2 Illite* (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/m 2/m

71.2.2d.3 Vermiculite (Mg,Fe,Al)3(Al,Si)4O10(OH)2·4(H2O) C 2/m 2/m

71.2.2d.4 Brammallite* (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/c 2/m

Strunz Class:

VIII/H.18-70 VIII - Silicates

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

VIII/H.18 - Smectite/Montmorillonite group

VIII/H.18-05 Lunijianlaite LiAl6(Si7Al)O20(OH)10 Unk Mono

VIII/H.18-07 Saliotite Na0.5Li0.5Al3AlSi3O10(OH)5 C 2/m 2/m

VIII/H.18-10 Kulkeite Na0.35Mg8AlSi7O20(OH)10 Unk Mono

VIII/H.18-20 Aliettite [Mg3Si4O10(OH)2](Ca0.5,Na)0.33(Al,Mg,Fe)2-3(Si,Al)4O10(OH)2·n(H2O) Unk Mono

VIII/H.18-30 Rectorite (Na,Ca)Al4(Si,Al)8O20(OH)4·2(H2O) Unk Mono

VIII/H.18-50 Tosudite Na0,5(Al,Mg)6(Si,Al)8O18(OH)12·5(H2O) Unk Ortho

VIII/H.18-60 Corrensite (Ca,Na,K)(Mg,Fe,Al)9(Si,Al)8O20(OH)10·n(H2O) Unk Ortho

VIII/H.18-70 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

Other Hydrobiotite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

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Hydrobiotite

[K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2]·[(Mg,Fe++,Al)3(Si,Al)4O10(OH)2·4(H2O)]
Dana No: 71.2.2d.1 Strunz No: VIII/H.18-70
Locality:

Notes: