It is a pseudomorph after a mineral with a layered structure, possibly some mineral of the mica group. Color is usually greenish yellow, yellow or brown. Luster is dull. Diaphaneity is translucent. Crystal Habits include sharp pseudo-hexagonal prismatic pseudomorphs to 5mm terminated with pinacoid.
Fracture is uneven.
Hardness is 2 - 2.5. Streak is white. Associated Minerals include aegirine, allanite, apophyllite series, calcite, microcline, natrolite, rhodochrosite and titanite.