Crystals are more common than massive forms, but localities with gem grade crystals are scattered and scarce. The crystals can be well shaped and show a nice monoclinic dipyramidal to tabular form. Lazulite although most crystals are dull, some exceptional specimens can be quite spectacular. Color is dark azure-blue to a bright indigo blue or even a pale sky blue. Luster is vitreous to dull.
Specimens are translucent to less commonly transparent.
Also granular and massive. Cleavage is distinct in one direction. Fracture is uneven. Hardness is 5.5 - 6. Streak is pale blue to white.