what type of rock is flint

Flint is a type of sedimentary rock composed primarily of cryptocrystalline or microcrystalline quartz (silicon dioxide, SiO2). It typically forms as nodules or layers within chalk or other soft limestones. Flint has a glassy or waxy appearance and breaks with a characteristic conchoidal fracture, making sharp edges. It is considered a variety of chert and is recognized for its hardness and ability to produce sparks when struck against steel, historically used for tools and fire-starting.