Luster is vitreous to pearly. Crystals are generally translucent and rarely transparent. Crystal Habits include rare individual crystals that have a stubby prismatic habit. More typically massive or in coarse lamellar or fibrous aggregates. Cleavage is perfect in two directions at nearly 90 degrees.
Fracture is uneven.
Hardness is 5 - 6. Streak is white. Associated Minerals include iron and stony meteorites, olivine , biotite , quartz , feldspars such as labradorite and certain types of garnets such as almandine . Notable Occurrences include the North Creek, New York, USA and Labrador, Canada. Best Field Indicators are color, crystal habit, hardness, cleavage, index of refraction and luster.