Benstonite Mineral Data

General Benstonite Information

Chemical Formula:

(Ba,Sr)6(Ca,Mn)6Mg(CO3)13

Composition:

Molecular Weight = 1,816.58 gm

Barium 34.02 % Ba 37.98 % BaO

Strontium 7.24 % Sr 8.56 % SrO

Calcium 9.93 % Ca 13.89 % CaO

Magnesium 1.34 % Mg 2.22 % MgO

Manganese 4.54 % Mn 5.86 % MnO

Carbon 8.60 % C 31.49 % CO₂

Oxygen 34.35 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ba_4.5Sr_1.5Ca_4.5Mn²⁺_1.5Mg(CO₃)₁₃

Environment:

Barite deposit.

IMA Status:

Approved IMA 1961

Locality:

Magnet Cove, Arkansas, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Orlando J. Benston (1901-1966), metallurgist for the Baroid Division, National Lead Co., Malvern, Arkansas, USA, who supplied the first specimens.

Name Pronunciation:

Benstonite + Pronunciation

Synonym:

ICSD 100479

PDF 14-637

Benstonite Image

Images:

Benstonite

Comments: Light pink benstonite crystals epitaxially formed on calcite needles.
Location: Minerva #1 Mine, Hardin County, Illinois, USA. Scale: 13 x 11 mm.
© John Veevaert

Benstonite Crystallography

Axial Ratios:

a:c = 1:0.47428

Cell Dimensions:

a = 18.28, c = 8.67, Z = 3; V = 2,509.01 Den(Calc)= 3.61

Crystal System:

Trigonal - Pyramidal H-M Symbol (3) Space Group: R 3

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

By Intensity(I/I_o): 3.08(1), 3.92(0.4), 2.536(0.3),

Physical Properties of Benstonite

Cleavage:

{???} Good

Color:

Snow white, Yellow brown, White, Light yellow.

Density:

3.596 - 3.66, Average = 3.62

Diaphaneity:

Translucent

Hardness:

3-4 - Calcite-Fluorite

Luminescence:

Fluorescent and phosphorescent, Short UV=yellow to red, Long UV=yellow to red.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Benstonite

Dichroism (e):

colorless.

Dichroism (w):

colorless.

Gladstone-Dale:

CI meas= 0.028 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.024 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1686,KPDmeas= 0.1677,KC= 0.1726
Ncalc = 1.62 - 1.63

Optical Data:

Uniaxial (-), e=1.527, w=1.69, bire=0.1630.

Calculated Properties of Benstonite

Electron Density:

Bulk Density (Electron Density)=3.33 gm/cc
note: Specific Gravity of Benstonite =3.61 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_Benstonite= 158.66 barns/electron
U=PE_Benstonite x rElectron Density= 528.74 barns/cc.

Radioactivity:

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

Benstonite Classification

Dana Class:

14.02.03.01 (14)Anhydrous Carbonates

(14.02)with Compound Formula A+ B++ (CO3)2

(14.02.03)Dana Group

14.02.03.01 Benstonite (Ba,Sr)6(Ca,Mn)6Mg(CO3)13 R 3 3

Strunz Class:

05.AB.55 05 - CARBONATES (NITRATES)

05.A - Carbonates without additional anions, without H2O

05.AB -Alkali-earth (and other M2+) carbonates

05.AB.55 Benstonite (Ba,Sr)6(Ca,Mn)6Mg(CO3)13 R 3 3

Other Benstonite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Benstonite :
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
15 - WWW-MINCRYST

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

Benstonite

(Ba,Sr)6(Ca,Mn)6Mg(CO3)13
Dana No: 14.02.03.01 Strunz No: 05.AB.55
Locality:

Notes:

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