- Appearance: Violet or purple-colored crystals that are transparent to translucent.

- Texture: Crystalline and hard, with a glassy luster.

- Solubility: Moderately soluble in water, producing a clear solution.

Anhydrous potassium alum:

- Appearance: White or colorless crystalline powder.

- Texture: Fine and powdery, without a distinct luster.

- Solubility: More soluble in water compared to hydrated potassium alum, producing a clear solution.