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Bentorite

Big Photo

Hatrurim Formation, Negev desert, Israel
© Paul Bongaerts

Show Bentorite Photos (5)
Formula:
Ca
 
6
(Cr
3+
 
,Al)
 
2
[(OH)
 
4
|SO
 
4
]
 
3
 · 26H
 
2
O
System:HexagonalColour:Violet
Lustre:VitreousHardness:2
Name:After Professor Y.K. Bentor, University of California, San Diego, for his contributions to the geology and mineralogy of Israel.
This page provides mineralogical data about Bentorite.

Classification of Bentorite

IMA status:Approved 1979
Strunz 8th edition ID:6/D.13-20
Strunz 9th edition ID:7.DG.15
Nickel-Strunz 10th (pending) edition ID:7.DG.15

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
G : With large and medium-sized cations; with NO3, CO3, B(OH)4, SiO4 or IO3
Dana 8th edition ID:31.10.2.2

31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
10 : Miscellaneous
Hey's CIM Ref.:25.4.14

25 : Sulphates
4 : Sulphates of Ca, Sr and Ba
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Type Occurrence of Bentorite

Type Locality:Hatrurim Formation, Negev desert, Israel
Year of Discovery:1980

Physical Properties of Bentorite

Lustre:Vitreous
Colour:Violet
Hardness (Mohs):2

Crystallography of Bentorite

Crystal System:Hexagonal
Cell Parameters:a = 22.35Å, c = 21.41Å
Ratio:a:c = 1 : 0.958
Unit Cell Volume:V 9,261.95 ų (Calculated from Unit Cell)
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data: Peaks:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Bentorite

Type:Uniaxial (+)
RI values: nω = 1.478 nε = 1.484
Maximum Birefringence:δ = 0.006

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate

Chemical Properties of Bentorite

Formula:
Ca
 
6
(Cr
3+
 
,Al)
 
2
[(OH)
 
4
|SO
 
4
]
 
3
 · 26H
 
2
O
Essential elements:Ca, Cr, H, O, S
All elements listed in formula:Al, Ca, Cr, H, O, S

Relationship of Bentorite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
7.DG.05Darapskite
Na
 
3
NO
 
3
SO
 
4
·H
 
2
O
7.DG.10Clinoungemachite
(Na, K, Fe, SO
 
4
)
7.DG.10Humberstonite
Na
 
7
K
 
3
Mg
 
2
(SO
 
4
)
 
6
(NO
 
3
)
 
2
·6H
 
2
O
7.DG.10Ungemachite
K
 
3
Na
 
8
Fe(SO
 
4
)
 
6
(NO
 
3
)
 
2
·6H
 
2
O
7.DG.15Charlesite
Ca
 
6
(Al,Si)
 
2
[(OH,O)
 
12
|B(OH)
 
4
|(SO
 
4
)
 
2
] · 26H
 
2
O
7.DG.15Ettringite
Ca
 
6
Al
 
2
[(OH)
 
4
|SO
 
4
]
 
3
 · 26H
 
2
O
7.DG.15Jouravskite
Ca
 
6
Mn
3+
2
[(OH)
 
4
|(SO
 
4
,CO
 
3
)]
 
3
 · 26H
 
2
O
7.DG.15Sturmanite
Ca
 
6
(Fe
3+
 
,Al,Mn
3+
 
)
 
2
[(OH)
 
12
|B(OH)
 
4
|(SO
 
4
)
 
2
] · 25H
 
2
O
7.DG.15Thaumasite
Ca
 
3
[CO
 
3
|SO
 
4
|Si(OH)
 
6
] · 12H
 
2
O
7.DG.15Carraraite
Ca
 
3
Ge(OH)
 
6
(SO
 
4
)(CO
 
3
)·12H
 
2
O
7.DG.15Buryatite
Ca
 
3
(Si,Fe,Al)[SO
 
4
][B(OH)
 
4
](OH)
 
5
O•
 
12
H
 
2
O
7.DG.20Rapidcreekite
Ca
 
2
[CO
 
3
|SO
 
4
] · 4H
 
2
O
7.DG.20Korkinoite
Ca, SO
 
4
, H
 
2
O reported
7.DG.25Tatarskite
Ca
 
6
Mg
 
2
(SO
 
4
)
 
2
(CO
 
3
)
 
2
Cl
 
4
(OH)
 
4
·7H
 
2
O
7.DG.30Nakauriite
Cu
 
8
[(OH)
 
6
|CO
 
3
|(SO
 
4
)
 
4
] · 48H
 
2
O
7.DG.35Chessexite
(Na,K)
 
4
Ca
 
2
(Mg,Zn)
 
3
Al
 
8
[(SO
 
4
)
 
10
|(SiO
 
4
)
 
2
] · 40H
 
2
O
7.DG.40Carlosruizite
K
 
6
(Na,K)
 
4
Na
 
6
Mg
 
10
(SeO
 
4
)
 
12
(IO
 
3
)
 
12
·12H
 
2
O
7.DG.40Fuenzalidaite
K
 
6
(Na,K)
 
4
Na
 
6
Mg
 
10
(SO
 
4
)
 
12
(IO
 
3
)
 
12
·12H
 
2
O
7.DG.45Chelyabinskite
(Ca,Mg)
 
3
[(SO
 
4
,CO
 
3
)
 
2
|Si(OH)
 
6
] · 9H
 
2
O (?)
Related Minerals - Hey's Index Grouping:

- +
25.4.1Anhydrite
CaSO
 
4
25.4.2Bassanite
Ca[SO
 
4
] · 0.5H
 
2
O
25.4.3Gypsum
Ca[SO
 
4
] · 2H
 
2
O
25.4.4Glauberite
Na
 
2
Ca(SO
 
4
)
 
2
25.4.5Cesanite
Na
 
3
Ca
 
2
[OH|(SO
 
4
)
 
3
]
25.4.6Eugsterite
Na
 
4
Ca(SO
 
4
)
 
3
·2H
 
2
O
25.4.7Hydroglauberite
Na
 
10
Ca
 
3
(SO
 
4
)
 
8
·6H
 
2
O
25.4.8Syngenite
K
 
2
Ca(SO
 
4
)
 
2
·H
 
2
O
25.4.9Görgeyite
K
 
2
Ca
 
5
(SO
 
4
)
 
6
·H
 
2
O
25.4.10Polyhalite
K
 
2
Ca
 
2
Mg(SO
 
4
)
 
4
·2H
 
2
O
25.4.11Koktaite
(NH
 
4
)
 
2
Ca(SO
 
4
)
 
2
·H
 
2
O
25.4.12Ye'elimite
Ca
 
4
Al
 
6
[O
 
12
|SO
 
4
]
25.4.13Ettringite
Ca
 
6
Al
 
2
[(OH)
 
4
|SO
 
4
]
 
3
 · 26H
 
2
O
25.4.15Celestine
SrSO
 
4
25.4.16Kalistrontite
K
 
2
Sr(SO
 
4
)
 
2
25.4.17Baryte
BaSO
 
4

Other Names for Bentorite

Synonyms:
IMA1979-042
Other Languages:
German:Bentorit
Spanish:Bentorita

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Bentorite

Reference List:Gross, S. (1980) Bentorite. A new mineral from the Hatrurim Area, west of
the Dead Sea, Israel. Israel J. of Earth Sci., 29, 81–84. [abstract in Amer. Mineral., 66 (1981), 639]

American Mineralogist: 66: 637.

Internet Links for Bentorite

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    Localities for Bentorite

    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Israel
     
    • Negev desert
    		Gross, S. (1977): The Mineralogy of the Hatrurim Formation, Israel. Geological Survey of Israel, Bulletin no. 70, 80 pp.
    Mineral and/or Locality
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    Copyright © Jolyon Ralph and Ida Chau 1993-2009. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 2nd Nov 2009 13:23:02