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Benstonite

A valid IMA mineral species
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About BenstoniteHide

Formula:
Ba6Ca6Mg(CO3)13
Ba may be replaced by minor Sr, and Ca by minor Mn.
Colour:
White to ivory, very pale yellow, pale yellowish brown
Lustre:
Vitreous
Hardness:
3 - 4
Specific Gravity:
3.956
Crystal System:
Trigonal
Name:
Named in honor of Orlando J. Benston (February 1901, Whalan, Minnesota, USA - 20 January 1966, Malvern, Arkansas, USA), an ore dressing metallurgist for the Baroid Division, National Lead Co., Malvern, Arkansas, USA, who supplied the first specimens.
Compare the chemically very similar alstonite and its dimorphs.


Unique IdentifiersHide

Mindat ID:
626
Long-form identifier:
mindat:1:1:626:8

Similar NamesHide

BentoniteA rock subtype

IMA Classification of BenstoniteHide

Classification of BenstoniteHide

5.AB.55

5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
B : Alkali-earth (and other M2+) carbonates
14.2.3.1

14 : ANHYDROUS NORMAL CARBONATES
2 : AB(XO3)2
11.5.7

11 : Carbonates
5 : Carbonates of Sr and Ba

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
BenIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of BenstoniteHide

Vitreous
Transparency:
Translucent
Colour:
White to ivory, very pale yellow, pale yellowish brown
Streak:
White
Hardness:
3 - 4 on Mohs scale
Cleavage:
Distinct/Good
Good on (31_42)
Density:
3.956 g/cm3 (Measured)    3.695 g/cm3 (Calculated)

Optical Data of BenstoniteHide

Type:
Uniaxial (-)
RI values:
nω = 1.690 nε = 1.527
Max. Birefringence:
δ = 0.163
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.

Surface Relief:
Moderate

Chemistry of BenstoniteHide

Mindat Formula:
Ba6Ca6Mg(CO3)13

Ba may be replaced by minor Sr, and Ca by minor Mn.
Element Weights:
Element% weight
Ba44.089 %
O33.388 %
Ca12.867 %
C8.355 %
Mg1.301 %

Calculated from ideal end-member formula.

Crystallography of BenstoniteHide

Crystal System:
Trigonal
Class (H-M):
3 - Rhombohedral
Space Group:
R3
Cell Parameters:
a = 18.280 Å, c = 8.652 Å
Ratio:
a:c = 1 : 0.473
Unit Cell V:
2,503.80 ų (Calculated from Unit Cell)
Z:
3
Morphology:
Rhombohedral crystals to 1cm.

Crystal StructureHide

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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0014709BenstoniteEffenberger H (1979) Kristallstruktur und chemische formel des benstonits, Ba6Ca6Mg(CO3)13 Neues Jahrbuch fur Mineralogie, Abhandlungen 136 326-33719790293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Loading XRD data...
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacingIntensity
3.08 Å(95)
3.92 Å(38)
2.536 Å(28)
2.127 Å(23)
1.905 Å(17)
4.19 Å(16)
3.53 Å(10)
Comments:
Magnet Cove, Arkansas, USA. Data from the type description. The intensity of the strongest peak is given as 95, rather than 100.

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
High-? alteration and/or metamorphism
32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits
Stage 4b: Highly evolved igneous rocks>3.0
36 : Carbonatites, kimberlites, and related igneous rocks
Geological Setting:
Barite deposits

Type Occurrence of BenstoniteHide

General Appearance of Type Material:
White cleavable masses, with cleavage faces to 1 cm across.
Place of Conservation of Type Material:
Mineralogische Sammlungen, Mineralogisch-Petrographisches Institut, Universität Göttingen, Göttingen, Germany, number S.21.3.5.1 (holotype).
National Museum of Natural History, Washington, D.C., USA numbers 120234 and 120236 (type).
Geological Setting of Type Material:
Baryte deposit.
Associated Minerals at Type Locality:

Other Language Names for BenstoniteHide

German:Benstonit
Simplified Chinese:菱碱土矿
Spanish:Benstonita

Common AssociatesHide

Associations Based on Photo Data:
47 photos of Benstonite associated with FluoriteCaF2
30 photos of Benstonite associated with CalciteCaCO3
14 photos of Benstonite associated with AlstoniteBaCa(CO3)2
8 photos of Benstonite associated with BaryteBaSO4
7 photos of Benstonite associated with SphaleriteZnS
1 photo of Benstonite associated with WitheriteBaCO3

Related Minerals - Strunz-mindat GroupingHide

5.AB.05SideriteFeCO3Trig. 3m(32/m) : R3c
5.AB.05RhodochrositeMnCO3Trig. 3m(32/m) : R3c
5.AB.05CalciteCaCO3Trig. 3m(32/m) : R3c
5.AB.05SmithsoniteZnCO3Trig. 3m(32/m) : R3c
5.AB.05GaspéiteNiCO3Trig. 3m(32/m) : R3c
5.AB.05SpherocobaltiteCoCO3Trig. 3m(32/m) : R3c
5.AB.05MagnesiteMgCO3Trig. 3m(32/m) : R3c
5.AB.05OtaviteCdCO3Trig. 3m(32/m) : R3c
5.AB.05 va'Parakutnohorite'
5.AB.10DolomiteCaMg(CO3)2Trig. 3 : R3
5.AB.10MinrecorditeCaZn(CO3)2Trig. 3 : R3
5.AB.10ŠkáchaiteCaCo(CO3)2Trig. 3 : R3
5.AB.10AnkeriteCa(Fe2+,Mg)(CO3)2Trig. 3 : R3
5.AB.10KutnohoriteCaMn2+(CO3)2Trig. 3 : R3
5.AB.15AragoniteCaCO3Orth. mmm(2/m2/m2/m)
5.AB.15CerussitePbCO3Orth. mmm(2/m2/m2/m)
5.AB.15WitheriteBaCO3Orth. mmm(2/m2/m2/m)
5.AB.15StrontianiteSrCO3Orth. mmm(2/m2/m2/m)
5.AB.20VateriteCaCO3Hex. 6/mmm(6/m2/m2/m) : P63/mmc
5.AB.25HuntiteCaMg3(CO3)4Trig. 32 : R32
5.AB.30NorsethiteBaMg(CO3)2Trig. 32 : R32
5.AB.35AlstoniteBaCa(CO3)2Tric.
5.AB.40ParalstoniteBaCa(CO3)2Trig. 32 : P321
5.AB.40OlekminskiteSr(Sr,Ca,Ba)(CO3)2Trig. 32 : P321
5.AB.45BarytocalciteBaCa(CO3)2Mon. 2/m : P21/m
5.AB.50Carbocernaite(Ca,Na)(Sr,Ce,Ba)(CO3)2Orth. mm2
5.AB.60JuangodoyiteNa2Cu(CO3)2Mon. 2/m : P21/b

Fluorescence of BenstoniteHide

Red or yellow in SW-UV, LW-UV, or X-rays.
Red phosphorescence.

Other InformationHide

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

Internet Links for BenstoniteHide

References for BenstoniteHide

Reference List:

Localities for BenstoniteHide

Showing 26 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
Canada
 
  • Saskatchewan
Shang (2000)
  • Yukon
    • Watson Lake mining district
      • Macmillan Pass
Gardner et al. (1985)
Ansdell et al. (1989)
China
 
  • Inner Mongolia
    • Baotou City
      • Bayan Obo mining district
        • Bayan Obo deposit
Youbin Liang et al. (1981)
Greece
 
  • Eastern Macedonia and Thrace
    • Evros
      • Alexandroupoli
Skarpelis et al. (2004)
India
 
  • Tamil Nadu
    • Krishnagiri District
Semenov et al. (1971) +2 other references
    • Salem District
      • Salem
Kumar et al. (2001)
    • Tirupattur District
Pavel M. Kartashov (n.d.) +1 other reference
    • Vellore District
Ramasamy et al. (2013)
Italy
 
  • Tuscany
    • Lucca Province
      • Stazzema
        • Sant'Anna di Stazzema
Biagioni et al. (2010)
Namibia
 
  • ǁKaras Region
    • Oranjemund Constituency
      • Rosh Pinah
Bode Verlag GmbH et al. (in English) +2 other references
Romania
 
Hirtopanu (2006)
Russia
 
  • Aldan Shield
    • Chara and Tokko Rivers Confluence
Mineralogical Society of America - ...
Vladykin et al. (2018)
  • Irkutsk Oblast
Vladykin et al. (2008)
    • Vitim Plateau
      • Biraya and Bya Rivers confluence area (Chara Basin)
Konev A A et al. (2004) +1 other reference
Konev A. A. +4 other references
Sweden
 
  • Värmland County
    • Filipstad
      • Långban Ore District
Holtstam et al. (1999)
USA
 
  • Arkansas
    • Hot Spring County
      • Magnet Cove
        • Chamberlain Creek Valley
Rocks & Min.:63:108 +1 other reference
Lippmann (1962)
Smith et al. (1996)
  • Illinois
    • Hardin County
      • Cave-In-Rock Mining Sub-District
Goldstein (1997)
        • Ozark-Mahoning group
Rocks & Minerals: 63: 217. +1 other reference
  • Texas
    • Houston County
Smith (1991)
Smith (1991)
Smith (1991)
 
and/or  
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