Bastnasite has been found in karst bauxite deposits in Hungary, Greece and the Balkans. At Mountain Pass, bastnasite is the leading ore mineral. Hydrothermal sources have also been reported. Color is pale white, tan, gray, brown, yellow and pink. Luster is pearly, vitreous, greasy to dull.
Crystals are translucent to opaque.
Crystal System is hexagonal. Crystal Habits include small hexagonal rounded flakes and short prismatic crystals, also in rosettes and spheres as well as massive and granular. Fracture is uneven. Hardness is 4 to 4.5. Streak is white.