The chemical compound represented by CaCl2.2H2O is calcium chloride dihydrate. Calcium chloride dihydrate is an extremely rare evaporite, sometimes referred to as "sinjarite," in honor of the locality in Iraq in which it was discovered in 1980. Sinjarite is produced by the evaporation and crystallization of dissolved limestone.
Sinjarite has a pale pink appearance. Its tetragonal crystals have an elongated prismatic shape. It can hold water extremely well and can even absorb moisture from the air. On the Mohs scale of mineral hardness, it is a 1 1/2. Even though there are no health concerns associated with the mineral, it is advisable to treat it with care, like with all minerals.