Color is usually dark red or red brown. Luster is vitreous. Diaphaneity is opaque. Crystal Habits include tabular crystals terminated by pinacoids to 3mm, glassy plates and blobs.
Fracture is conchoidal.
Hardness is 4 - 5. Streak is black. Associated Minerals include aegirine, eudialyte, lueshite, sodalite, villiaumite and vuonnemite. Danish geologist who discovered the mineral.