Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Habit:
Massive - Granular - Common texture observed in granite and other igneous rock.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Hardness:
4-4.5 - Between Fluorite and Apatite
Luster:
Vitreous - Greasy
Streak:
white
Optical Properties of Bastnasite-(Y)
Gladstone-Dale:
CI meas= 0.114 (Poor) - where the CI = (1-KPDmeas/KC) CI calc= 0.07 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1626,KPDmeas= 0.1551,KC= 0.1749 Ncalc = 1.83 - 1.87
Optical Data:
Uniaxial (+), w=1.717, e=1.818, bire=0.1010.
Calculated Properties of Bastnasite-(Y)
Electron Density:
Bulk Density (Electron Density)=4.39 gm/cc note: Specific Gravity of Bastnasite-(Y) =4.72 gm/cc.
Fermion Index:
Fermion Index = 0.0009240483 Boson Index = 0.9990759517
Photoelectric:
PEBastnasite-(Y) = 67.02 barns/electron U=PEBastnasite-(Y) x rElectron Density= 293.90 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Bastnasite-(Y) is Not Radioactive