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Crystal Structure:
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Ghose S , Sen Gupta P K , Schlemper E O , American Mineralogist , 70 (1985) p.1248-1252, Electron ordering in ilvaite, a mixed-valence iron, silicate: crystal structure refinement at 138 K, Sample: T = 138 K
Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Habit:
Columnar - Forms columns
Habit:
Massive - Uniformly indistinguishable crystals forming large masses.
Habit:
Striated - Parallel lines on crystal surface or cleavage face.
Hardness:
5.5-6 - Knife Blade-Orthoclase
Luminescence:
Non-fluorescent.
Luster:
Sub Metallic
Streak:
brownish black
Optical Properties of Ilvaite
Gladstone-Dale:
CI meas= -0.046 (Good) - where the CI = (1-KPDmeas/KC) CI calc= -0.033 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2031,KPDmeas= 0.2056,KC= 0.1966 Ncalc = 1.78 - 1.8
Optical Data:
Biaxial (-), a=1.727, b=1.87, g=1.883, bire=0.1560, 2V(Calc)=30, 2V(Meas)=20-30. Dispersion strong, r < v.
Calculated Properties of Ilvaite
Electron Density:
Bulk Density (Electron Density)=3.96 gm/cc note: Specific Gravity of Ilvaite =4.07 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PEIlvaite = 14.01 barns/electron U=PEIlvaite x rElectron Density= 55.51 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Ilvaite is Not Radioactive
Ilvaite Classification
Dana Class:
56.02.03.03(56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O
(56.02)with cations in [4] and/or >[4] coordination