Halite is a common evaporite mineral, NaCl, used as table salt worldwide. It is arguably the most well-known mineral in the world. It has a formula unit composition of NaCl, and is in the cubic crystal system. In pure form it is nearly transparent or white.
Rotation of the halite structure such that you are looking at an axis going from one corner of the cube to the opposite corner will show the six-fold internal symmetry of the structure.
This water soluble mineral is found in sedimentary deposits. Used as table salt, large deposits are found in Poland, Germany, Austria, Italy and China. It is a major component of saline and salt-affected soils, and causes dispersion of clays, making it difficult to leach the NaCl from the soil unless a flocculating agent (such as gypsum) is added.
Finger, L.W., and H. King. 1978. A revised method of operation of the single-crystal diamond cell and refinement of the structure of NaCl at 32 kbar. American Mineralogist. 63:337-342.