Ammonium Magnesium Sulfate
occurs in nature as mineral boussingaultite
monoclinic prismatic
this crystal shows 14 faces
pinacoid {010}      d = 1.100   2 faces
pinacoid {001}      d = 1.200   2 faces
pinacoid {20-1}      d = 1.300   2 faces
monoclinic prism {110}      d = 0.800   4 faces
monoclinic prism {011}      d = 1.200   4 faces
unit cell :  a = 9.30  b = 12.60  c = 6.21
β = 107.10 (beta)