Luster is vitreous to greasy. Crystals are commonly opaque but can be found translucent. The terminations are usually wedge shaped, more rarely tapered pyramids. Also massive or as is most commonly the case, as embedded grains. Cleavage poor in one direction, lengthwise.
Fracture is conchoidal.
Hardness is 5.5 Specific Gravity is 3.0 - 4.2 Streak is black. Twinning may be seen as parallel grooves and allanite has slight radioactivity. Best Field Indicators are crystal habit, color, radioactivity, luster and hardness.