Water is the universal solvent .
Suspended materials weigh less in water than they would in air. The heft or specific gravity of a mineral reflects its degree of bouyancy. The specific gravity of quartz is 2.6, meaning that a chunk of quartz is 2.6 times heavier than an equal volume of water. There are two kinds of valleys, narrow and broad, which result from the predominance of downcutting or lateral cutting, respectively. Lateral cutting by the river produces landslips and rockslides, widening the valley.