Chert

Description 

Chert is a hard, fine-grained sedimentary rock composed of the mineral form of silicon dioxide, quartz. It occurs as nodules, concretionary masses, and as layered deposits.

Application and Uses

In some areas, chert is used as a construction material and road surfacing. When used in road surfacing, chert becomes compact and firm when it comes into contact with rain. In comparison, other fill often becomes muddy.