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.
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Effenberger H , Neues Jahrbuch fur Mineralogie, Abhandlungen , 136 (1979) p.326-337, Kristallstruktur und chemische formel des benstonits, Ba6Ca6Mg(CO3)13
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:
PEBenstonite = 158.66 barns/electron U=PEBenstonite x rElectron Density= 528.74 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Benstonite is Not Radioactive