Beidellite Mineral Data

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.

Name Pronunciation:

Beidellite + Pronunciation

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

Diaphaneity:

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
Ncalc = 1.42 - 1.5

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:

Bulk Density (Electron Density)=2.15 gm/cc
note: Specific Gravity of Beidellite =2.15 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Beidellite= 1.54 barns/electron
U=PE_Beidellite x rElectron Density= 3.32 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Beidellite is Not Radioactive

Beidellite Classification

Dana Class:

71.03.01a.01 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.03)with 2:1 clays

(71.03.01a)Smectite group (Dioctahedral Smectites)

71.03.01a.01 Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2•n(H2O) C 2/m or ORTH 2/m

71.03.01a.02 Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2•n(H2O) C 2/m 2/m

71.03.01a.03 Nontronite Na0.3Fe2(Si,Al)4O10(OH)2•n(H2O) C 2/m 2/m

71.03.01a.04 Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m

71.03.01a.05 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:

09.EC.40 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets

09.EC.40 Almbosite? Fe5Fe4V4Si3O27 Ortho ? Ortho

09.EC.40 Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2•n(H2O) C 2/m or ORTH 2/m

09.EC.40 Kurumsakite (Zn,Ni,Cu)8Al8V2Si5O35•27(H2O)(?) Unk Ortho

09.EC.40 Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2•n(H2O) C 2/m 2/m

09.EC.40 Nontronite Na0.3Fe2(Si,Al)4O10(OH)2•n(H2O) C 2/m 2/m

09.EC.40 Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m

09.EC.40 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)

See Also:

Links to other databases for Beidellite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Ask about Beidellite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Beidellite

Na0.5Al2(Si3.5Al0.5)O10(OH)2•n(H2O)
Dana No: 71.03.01a.01 Strunz No: 09.EC.40
Locality:

Notes: