Specimens are translucent to transparent. Crystal System is triclinic, 1. Crystal Habits are pseudotetragonal and pseudocubic forming rectangular box or cube shaped crystals. Penetration twinning is common and forms flat square and elongated crystals. Aggregate rosettes are also seen.
Cleavage is perfect in one direction and fair in two others.
Hardness is 4. Streak is white. Associated Minerals include many rare and beautiful minerals such as aegirine , fluorite , rhodochrosite , serandite , albite , astrophyllite , natrolite , rhabdophane , analcime , ancylite , catapleiite , epididymite , microcline and behoite . Notable Occurrence includes the type locality of Langesundsfjord district, Norway as well as Mont Saint-Hilaire , Quebec, Canada and Kola Peninsula , Russia. Best Field Indicators are crystal habit, color, associations, locality and cleavage.