Hydrophilite is a white mineral formed from anhydrous

Anhydrous

As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another...

 calcium chloride

Calcium chloride

Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation...

. It is very soft and it forms crystal structures that are not used as gems. In Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, hydrophilite is spread on dirt roads to reduce dust. Hydrophilite crystallizes

Crystallization

Crystallization is the process of formation of solid crystals precipitating from a solution, melt or more rarely deposited directly from a gas. Crystallization is also a chemical solid–liquid separation technique, in which mass transfer of a solute from the liquid solution to a pure solid...

 in the form of encrustations and as crystals configrued similar to cubes. The crystal symmetry is orthorhombic, symbol (2/m 2/m 2/m), space group

Space group

In mathematics and geometry, a space group is a symmetry group, usually for three dimensions, that divides space into discrete repeatable domains.In three dimensions, there are 219 unique types, or counted as 230 if chiral copies are considered distinct...

Pnnm. Density is 2.22 g/cm³.