Basalt is a volcanic rock mass. It is an extra hard, black colored rock. Basalt has been being preferred as paving stones, building stones and a bridge material owing to its being a hard and durable rock since long. Today it is used as railway ballast material, asphalt aggregate, etc. in sub-base applications as well as in granule and powder form as an alternative and sanitary raw material in many other lines of business using silica and quartz sands in the past, since it does not contain free silica.