Crystals of powellite resemble the much more common but heavier crystals of scheelite, fortunately the difference in fluorescence is a key to distinguishing them. Color is yellow, brown, gray, blue, white or black. Luster is adamantine to greasy. Crystals are translucent to transparent. Commonly as crusts or films around altered molybdenite and as pseudomorphs after molybdenite.
Fracture is uneven.
Hardness is 3.5 - 4. Streak is white. Fluorescent golden yellow. Associated Minerals are quartz , zeolites , molybdenite and lindgrenite . Best Field Indicators are crystal habit, color, fluorescence, association with molybdenite and cleavage.