Common Forms/Occurrences: Common in dolomites and limestones Useful Identification Test: Soluble in H2SO4 with evolution of HF; slightly soluble in HCl Chemical formula: CaF2 Crystal System: Usually cubes Colour: Colourless, purple, blue, gray, green, or yellow Streak: White Lustre: Nonmetallic (NM) Cleavage: Excellent Fracture: Conchoidal to splintery; Brittle Hardness: 4 Hardness Search: four Specific Gravity: 3.0 - 3.3