Beidellite Mineral Data

Beidellite Mineral Data +

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General Beidellite Information

Chemical Formula:

Na0.5Al2(Si3.5Al0.5)O10(OH)2·n(H2O)

Composition:

Molecular Weight = 389.27 gm

Sodium 2.95 % Na 3.98 % Na₂O

Aluminum 17.33 % Al 32.74 % Al₂O₃

Silicon 25.25 % Si 54.02 % SiO₂

Hydrogen 1.04 % H 9.26 % H₂O

Oxygen 53.43 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na_0.5Al_2.5Si_3.5O₁₀(OH)₂·(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1925

Locality:

Beidell, Colorado, USA.. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Synonym:

Bentonite

Montmorillonite(Ca)

Montmorillonite(Na)

Beidellite Image

Images:

Beidellite

Comments: Pure white chalky massive beidellite.
Location: From near Charlestown, Nevis, Saint Kitts and Nevis, West Indies. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Beidellite Crystallography

Axial Ratios:

a:b:c =0.5755:1:1.6797

Cell Dimensions:

a = 5.14, b = 8.93, c = 15, Z = 2; beta = 99.54° V = 678.98 Den(Calc)= 1.90

Crystal System:

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

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

By Intensity(I/I_o): 2.55(1), 2.61(1), 4.52(1),

Physical Properties of Beidellite

Cleavage:

[001] Perfect

Color:

White, Gray, Reddish white, Brownish white, Pale yellow.

Density:

2 - 2.3, Average = 2.15

Diaphaniety:

Translucent to subtranslucent

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Hardness:

1-2 - Between Talc and Gypsum

Luminescence:

Non-fluorescent.

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Beidellite

Gladstone-Dale:

CI meas= -0.101 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.246 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2731,KPDmeas= 0.2413,KC= 0.2192

Optical Data:

Biaxial (-), a=1.494-1.503, b=1.525-1.532, g=1.526-1.533, bire=0.0300-0.0320, 2V(Calc)=20, 2V(Meas)=9-16. Dispersion none.

Calculated Properties of Beidellite

Electron Density:

r_electron=2.15 gm/cc
note: r_Beidellite=2.15 gm/cc.

Fermion Index

Fermion Index = 0.01205
Boson Index = 0.98795

Photoelectric:

PE_Beidellite= 1.54 barns/electron
U=PE_Beidellite x r_electron= 3.32 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Beidellite is Not Radioactive

Beidellite Classification

Dana Class:

71.3.1a.1 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.3)with 2:1 clays

(71.3.1a)Smectite group (Dioctahedral Smectites)

71.3.1a.1 Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2·n(H2O) C 2/m or ORTH 2/m

71.3.1a.2 Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2·n(H2O) C 2/m 2/m

71.3.1a.3 Nontronite Na0.3Fe2(Si,Al)4O10(OH)2·n(H2O) C 2/m 2/m

71.3.1a.4 Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2·4(H2O) C 2/m 2/m

71.3.1a.5 Swinefordite (Li,Ca0.5,Na)0.72(Li,Al,Mg)2.66(Si,Al)4O10(OH,F)2·2(H2O) C 2/m (MON or ORTH) 2/m

Strunz Class:

VIII/H.19-30 VIII - Silicates

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

VIII/H.19 - Brammallite ? - Yakhontovite series

VIII/H.19-10 Brammallite* (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/c 2/m

VIII/H.19-10a 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

VIII/H.19-15 Illite* (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/m 2/m

VIII/H.19-20 Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2·n(H2O) C 2/m 2/m

VIII/H.19-30 Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2·n(H2O) C 2/m or ORTH 2/m

VIII/H.19-40 Nontronite Na0.3Fe2(Si,Al)4O10(OH)2·n(H2O) C 2/m 2/m

VIII/H.19-50 Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2·4(H2O) C 2/m 2/m

VIII/H.19-60 Swinefordite (Li,Ca0.5,Na)0.72(Li,Al,Mg)2.66(Si,Al)4O10(OH,F)2·2(H2O) C 2/m (MON or ORTH) 2/m

VIII/H.19-70 Yakhontovite (Ca,K)0.5(Cu,Fe,Mg)2Si4O10(OH)2·3(H2O) C 2/m 2/m

Other Beidellite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

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

Beidellite

Na0.5Al2(Si3.5Al0.5)O10(OH)2·n(H2O)
Dana No: 71.3.1a.1 Strunz No: VIII/H.19-30
Locality:

Notes: