The Jaguaracu Pegmatite, Minas Gerais, Brazil. Also known as the Jose Miranda mine or the Ze Pinto or Jose Pinto mine. Link to MinDat.org Location Data.
Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces.
Habit:
Wheat Sheaf - Bundle shaped aggregates resembling wheat sheafs after hand reaping wheat.
Hardness:
6-7 - Orthoclase-Quartz
Luminescence:
Non-fluorescent.
Luster:
Vitreous - Dull
Streak:
pale purple white
Optical Properties of Minasgeraisite-(Y)
Gladstone-Dale:
CI meas= 0.073 (Fair) - where the CI = (1-KPDmeas/KC) CI calc= 0.081 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1772,KPDmeas= 0.1788,KC= 0.1928 Ncalc = 1.82 - 1.83