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Hassan I , Grundy H D , American Mineralogist , 70 (1985) p.186-192, The crystal structures of helvite group minerals, (MnFeZn)8(Be6Si6O24)S2
View Additional jPOWD Structure files for Genthelvite
[1]
Physical Properties of Genthelvite
Cleavage:
None
Color:
Blue green, Brown, Colorless, Green, Yellow.
Density:
3.62
Diaphaneity:
Transparent
Fracture:
Brittle - Uneven - Very brittle fracture producing uneven fragments.
Hardness:
6-6.5 - Orthoclase-Pyrite
Luminescence:
Phosphorescent fluorescent, Short UV=green, Long UV=green.
Luster:
Vitreous (Glassy)
Streak:
white
Optical Properties of Genthelvite
Gladstone-Dale:
CI meas= -0.146 (Poor) - where the CI = (1-KPDmeas/KC) CI calc= -0.122 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2009,KPDmeas= 0.2054,KC= 0.1792 Ncalc = 1.65 - 1.66
Optical Data:
Isotropic, n=1.742-1.745.
Calculated Properties of Genthelvite
Electron Density:
Bulk Density (Electron Density)=3.55 gm/cc note: Specific Gravity of Genthelvite =3.70 gm/cc.
Fermion Index:
Fermion Index = 0.07 Boson Index = 0.93
Photoelectric:
PEGenthelvite = 22.74 barns/electron U=PEGenthelvite x rElectron Density= 80.63 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Genthelvite is Not Radioactive