Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Habit:
Platy - Sheet forms (e.g. micas).
Hardness:
3-4 - Calcite-Fluorite
Luster:
Vitreous (Glassy)
Streak:
pale blue
Optical Properties of Calcioandyrobertsite-2O
Gladstone-Dale:
CI meas= 0.026 (Excellent) - where the CI = (1-KPDmeas/KC) CI calc= 0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1912,KPDmeas= 0.1863,KC= 0.1914 Ncalc = 1.73 - 1.75