Basalt is a hard, black volcanic rock with less than about 52 weight percent silica. Because of basalt’s low silica content, it has a low viscosity (resistance to flow). Basalt is erupted at
Basalt is a hard, black volcanic rock with less than about 52 weight percent silica. Because of basalt’s low silica content, it has a low viscosity (resistance to flow). Basalt is erupted at
