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Beidellite
A valid IMA mineral species - grandfathered
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About Beidellite
Formula:
(Na,Ca0.5)0.3Al2((Si,Al)4O10)(OH)2 · nH2O
Colour:
White, reddish, brownish-grey
Lustre:
Vitreous, Waxy
Hardness:
1 - 2
Specific Gravity:
2 - 3
Crystal System:
Monoclinic
Member of:
Name:
Named for the type locality at Beidell, Colorado, USA. Pronounced bei-dell'-ite.
Unique Identifiers
Mindat ID:
604
Long-form identifier:
mindat:1:1:604:6
IMA Classification of Beidellite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
(Na,Ca)0.3Al2(Si,Al)4O10(OH)2·nH2O
Classification of Beidellite
9.EC.40
9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
71.3.1a.1
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
3 : Sheets of 6-membered rings with 2:1 clays
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
3 : Sheets of 6-membered rings with 2:1 clays
16.11.17
16 : Silicates Containing Aluminum and other Metals
11 : Aluminosilicates of Ca and Mg with or without alkalis
16 : Silicates Containing Aluminum and other Metals
11 : Aluminosilicates of Ca and Mg with or without alkalis
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Bei | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Bei | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Bei | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261–264 doi:10.1180/clm.2020.30 |
Physical Properties of Beidellite
Vitreous, Waxy
Transparency:
Translucent
Colour:
White, reddish, brownish-grey
Hardness:
1 - 2 on Mohs scale
Cleavage:
Perfect
{001}
{001}
Density:
2 - 3 g/cm3 (Measured)
Comment:
depending on hydration.
Optical Data of Beidellite
Type:
Biaxial (-)
RI values:
nα = 1.494 - 1.503 nβ = 1.525 - 1.532 nγ = 1.526 - 1.533
2V:
Measured: 9° to 16°, Calculated: 20°
Max. Birefringence:
δ = 0.030 - 0.032
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Low (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
none
Chemistry of Beidellite
Mindat Formula:
(Na,Ca0.5)0.3Al2((Si,Al)4O10)(OH)2 · nH2O
Element Weights:
Common Impurities:
Ti,K,Mg,Fe
Crystallography of Beidellite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 5.17 Å, b = 8.97 Å, c = 17.57 Å
β = 90°
β = 90°
Ratio:
a:b:c = 0.576 : 1 : 1.959
Unit Cell V:
814.81 ų (Calculated from Unit Cell)
Comment:
Z = n.d.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 17.6 Å | (100) |
| 4.42 Å | (100) |
| 3.95 Å | (100) |
| 3.54 Å | (100) |
| 2.50 Å | (100) |
| 1.498 Å | (100) |
| 2.57 Å | (80) |
Comments:
glycolated, diffuse pattern.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 9 : Lava/xenolith minerals (hornfels, sanidinite facies) | |
| Near-surface Processes | |
| 22 : Hydration and low-? subsurface aqueous alteration (see also #23) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] |
Geological Setting:
A constituent of bentonitic clays; an alteration product in hydrothermal mineral deposits, especially porphyry Cu-Mo systems; in soils derived from mafic rocks.
Type Occurrence of Beidellite
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, R4762 (Black Jack mine, Idaho, USA); R4761 (Beidell, Colorado, USA, material determined to be a mixture in part).
Other Language Names for Beidellite
Varieties of Beidellite
| Aluminium Montmorillonite | A synthetic end-member in the montmorillonite series. |
| Chrome-Beidellite | A chromian Beidellite |
| Ferribeidellite | Fe(III)-bearing variety of beidellite. |
Relationship of Beidellite to other Species
Member of:
Other Members of Smectite Group:
| Ferrosaponite | Ca0.3(Fe2+,Mg,Fe3+)3((Si,Al)4O10)(OH)2 · 4H2O | Mon. |
| Hectorite | Na0.3(Mg,Li)3(Si4O10)(F,OH)2 | Mon. 2/m : B2/m |
| Montmorillonite | (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O | Mon. 2/m : B2/m |
| Nontronite | Na0.3Fe2((Si,Al)4O10)(OH)2 · nH2O | Mon. 2/m : B2/m |
| 'Pimelite' | Ni3Si4O10(OH)2 · 4H2O | Hex. |
| Saliotite | (Li,Na)Al3(AlSi3O10)(OH)5 | Mon. 2/m : B2/m |
| Saponite | Ca0.25(Mg,Fe)3((Si,Al)4O10)(OH)2 · nH2O | Mon. |
| Sauconite | Na0.3Zn3((Si,Al)4O10)(OH)2 · 4H2O | Mon. |
| Stevensite | (Ca,Na)xMg3-x(Si4O10)(OH)2 | Mon. |
| Swinefordite | Li(Al,Li,Mg)3((Si,Al)4O10)2(OH,F)4 · nH2O | Mon. 2/m : B2/m |
| Volkonskoite | Ca0.3(Cr,Mg,Fe)2((Si,Al)4O10)(OH)2 · 4H2O | Mon. |
| Yakhontovite | (Ca,Na)0.5(Cu,Fe,Mg)2(Si4O10)(OH)2 · 3H2O | Mon. |
| Zincsilite | Zn3Si4O10(OH)2 · 4H2O (?) | Mon. |
Forms a series with:
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 9.EC. | Meifuite | KFe6(Si7Al)O19(OH)4Cl2 |
| 9.EC. | Balestraite | KLi2V5+Si4O12 |
| 9.EC. | Voloshinite | Rb(LiAl1.5◻0.5)(Al0.5Si3.5)O10F2 |
| 9.EC.05 | Talc | Mg3Si4O10(OH)2 |
| 9.EC.05 | Minnesotaite | Fe2+3Si4O10(OH)2 |
| 9.EC.05 | Willemseite | Ni3Si4O10(OH)2 |
| 9.EC.10 | Fluorluanshiweiite | KLiAl1.5(Si3.5Al0.5)O10F2 |
| 9.EC.10 | Garmite | CsLiMg2(Si4O10)F2 |
| 9.EC.10 | Gorbunovite | CsLi2(Ti,Fe)Si4O10(F,OH,O)2 |
| 9.EC.10 | Ferripyrophyllite | Fe3+Si2O5(OH) |
| 9.EC.10 | Manganiceladonite | K(MgMn3+◻)(Si4O10)(OH)2 |
| 9.EC.10 | Luanshiweiite | KLiAl1.5(Si3.5Al0.5)O10(OH)2 |
| 9.EC.10 | Pyrophyllite | Al2Si4O10(OH)2 |
| 9.EC.15 | Paragonite | NaAl2(AlSi3O10)(OH)2 |
| 9.EC.15 | Ferroaluminoceladonite | K(Fe2+Al◻)(Si4O10)(OH)2 |
| 9.EC.15 | Nanpingite | CsAl2(AlSi3O10)(OH,F)2 |
| 9.EC.15 | Ferroceladonite | K(Fe2+Fe3+◻)(Si4O10)(OH)2 |
| 9.EC.15 | Ganterite | Ba0.5(Na,K)0.5Al2(Si2.5Al1.5)O10(OH)2 |
| 9.EC.15 | Kreiterite | CsLi2Fe3+(Si4O10)F2 |
| 9.EC.15 | Roscoelite | KV3+2(AlSi3O10)(OH)2 |
| 9.EC.15 | Aluminoceladonite | K(MgAl◻)(Si4O10)(OH)2 |
| 9.EC.15 | Tobelite | (NH4)Al2(AlSi3O10)(OH)2 |
| 9.EC.15 | Tainiolite | KLiMg2(Si4O10)F2 |
| 9.EC.15 | Celadonite | K(MgFe3+◻)(Si4O10)(OH)2 |
| 9.EC.15 | Chromceladonite | K(MgCr◻)(Si4O10)(OH)2 |
| 9.EC.15 | Montdorite | KFe2+1.5Mn2+0.5Mg0.5Si4O10(F,OH)2 |
| 9.EC.15 | Chromphyllite | KCr2(AlSi3O10)(OH)2 |
| 9.EC.15 | Boromuscovite | KAl2(BSi3O10)(OH)2 |
| 9.EC.15 | 'UM1988-22-SiO:AlCaFFeHKLiMg' | KLiMgAl2Si3O10F2 |
| 9.EC.15 | Chernykhite | (Ba,Na)(V3+,Al,Mg)2((Si,Al)4O10)(OH)2 |
| 9.EC.15 | Muscovite | KAl2(AlSi3O10)(OH)2 |
| 9.EC.20 | Masutomilite | K(LiAlMn2+)[AlSi3O10]F2 |
| 9.EC.20 | Oxyphlogopite | K(Mg,Ti,Fe)3[(Si,Al)4O10](O,F)2 |
| 9.EC.20 | 'Chloroferrokinoshitalite' | (Ba,K)(Fe2+,Mg)3(Al2Si2O10)(Cl,OH,F)2 |
| 9.EC.20 | Siderophyllite | KFe2+2Al(Al2Si2O10)(OH)2 |
| 9.EC.20 | Sokolovaite | CsLi2Al(Si4O10)F2 |
| 9.EC.20 | Hendricksite | KZn3(Si3Al)O10(OH)2 |
| 9.EC.20 | Tetraferriphlogopite | KMg3(Si3Fe3+)O10(OH)2 |
| 9.EC.20 | Fluorannite | KFe2+3(Si3Al)O10F2 |
| 9.EC.20 | Aspidolite | NaMg3(AlSi3O10)(OH)2 |
| 9.EC.20 | Suhailite | (NH4)Fe2+3(AlSi3O10)(OH)2 |
| 9.EC.20 | Ephesite | NaLiAl2(Al2Si2O10)(OH)2 |
| 9.EC.20 | Norrishite | KLiMn3+2(Si4O10)O2 |
| 9.EC.20 | Phlogopite | KMg3(AlSi3O10)(OH)2 |
| 9.EC.20 | Yangzhumingite | KMg2.5(Si4O10)F2 |
| 9.EC.20 | Orlovite | KLi2Ti(Si4O10)OF |
| 9.EC.20 | Tetraferriannite | KFe2+3(Si3Fe3+)O10(OH)2 |
| 9.EC.20 | Shirokshinite | K(NaMg2)(Si4O10)F2 |
| 9.EC.20 | Trilithionite | K(Li1.5Al1.5)(AlSi3O10)(F,OH)2 |
| 9.EC.20 | Polylithionite | KLi2Al(Si4O10)(F,OH)2 |
| 9.EC.20 | Shirozulite | KMn2+3(Si3Al)O10(OH)2 |
| 9.EC.20 | Preiswerkite | NaMg2Al(Al2Si2O10)(OH)2 |
| 9.EC.20 | Fluorophlogopite | KMg3(Si3Al)O10F2 |
| 9.EC.20 | Wonesite | (Na,K,◻)(Mg,Fe,Al)6(Si,Al)8O20(OH,F)4 |
| 9.EC.20 | 'UM2004-49-SiO:AlCsFHKLi' | (Cs,K)(Al,Li)2.6((Si,Al)4O10)(F,OH)2 |
| 9.EC.20 | Fluorotetraferriphlogopite | KMg3(Fe3+Si3O10)F2 |
| 9.EC.20 | Annite | KFe2+3(AlSi3O10)(OH)2 |
| 9.EC.20 | Eastonite | KMg2Al(Al2Si2O10)(OH)2 |
| 9.EC.22 | 'Pimelite' | Ni3Si4O10(OH)2 · 4H2O |
| 9.EC.30 | Margarite | CaAl2(Al2Si2O10)(OH)2 |
| 9.EC.35 | Kinoshitalite | (Ba,K)(Mg,Mn2+,Al)3(Al2Si2O10)(OH)2 |
| 9.EC.35 | Ferrokinoshitalite | (Ba,K)(Fe2+,Mg)3(Al2Si2O10)(OH,F)2 |
| 9.EC.35 | Clintonite | CaAlMg2(SiAl3O10)(OH)2 |
| 9.EC.35 | Oxykinoshitalite | (Ba,K)(Mg,Ti,Fe3+,Fe2+)3((Si,Al)4O10)(O,OH,F)2 |
| 9.EC.35 | Fluorokinoshitalite | BaMg3(Al2Si2O10)F2 |
| 9.EC.35 | Bityite | CaLiAl2(AlBeSi2O10)(OH)2 |
| 9.EC.35 | Anandite | (Ba,K)(Fe2+,Mg)3((Si,Al,Fe)4O10)(S,OH)2 |
| 9.EC.40 | Montmorillonite | (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O |
| 9.EC.40 | Volkonskoite | Ca0.3(Cr,Mg,Fe)2((Si,Al)4O10)(OH)2 · 4H2O |
| 9.EC.40 | Nontronite | Na0.3Fe2((Si,Al)4O10)(OH)2 · nH2O |
| 9.EC.40 | Kurumsakite | (Zn,Ni,Cu)8Al8V5+2Si5O35 · 27H2O (?) |
| 9.EC.40 | Yakhontovite | (Ca,Na)0.5(Cu,Fe,Mg)2(Si4O10)(OH)2 · 3H2O |
| 9.EC.45 | Swinefordite | Li(Al,Li,Mg)3((Si,Al)4O10)2(OH,F)4 · nH2O |
| 9.EC.45 | Hectorite | Na0.3(Mg,Li)3(Si4O10)(F,OH)2 |
| 9.EC.45 | Zincsilite | Zn3Si4O10(OH)2 · 4H2O (?) |
| 9.EC.45 | Hanjiangite | Ba2CaV3+Al(H2AlSi3O12)(CO3)2F |
| 9.EC.45 | Spadaite | MgSiO2(OH)2 · H2O (?) |
| 9.EC.45 | Ferrosaponite | Ca0.3(Fe2+,Mg,Fe3+)3((Si,Al)4O10)(OH)2 · 4H2O |
| 9.EC.45 | Stevensite | (Ca,Na)xMg3-x(Si4O10)(OH)2 |
| 9.EC.45 |
Cameron, Cameron Mining District, Coconino County, Arizona, USA