Anhydrite

$CaSO_4$

  Family sulfates
  Crystal system orthorhombiic
  Color white, white reddish, grey
  Streak color white
  Cleavage 3 cleavages (1 perfect, 2 good)
  Hardness 3,0 to 3,5
  Density 2,9 to 3,0

Explanations: → Here List of minerals: → Here