Luster is vitreous, also silky on sphericule's surfaces. Crystals are transparent to translucent. Sphericules are small tight balls that have a sparkling or silky luster in phillipsite. Aggregates can be radiating, fibrous, columnar and encrusting. Cleavage is imperfect in one direction.
Fracture is uneven.
Hardness is 4 - 4.5. Streak is white. Associated Minerals are quartz , calcite , chabazite , natrolite , heulandite , stilbite and other zeolites . Best Field Indicators are crystal habit, twinning, density, hardness and associations.