Perfect after {110}, distinct after {101} and {010}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Point Group
orthorhombic-dipyramidal - 2/m 2/m 2/m
Space Group
Pnma (62)
Habit
spherical, radial, grape-shaped
Formation
Secondary, resulting from hydrothermal alteration or supergene weathering of aluminum-bearing minerals/rocks under the influence of phosphoric acid solutions, often in fractures of siliceous shales
