flint

flint variety of quartz that commonly occurs in rounded nodules and whose crystal structure is not visible to the naked eye. Flint is dark gray, smoky brown, or black in color; pale gray flint is called chert. When found in chalk or in other rocks containing lime, the nodules frequently have a white coating. Flint is translucent to opaque. It was early used by primitive peoples for making knives and spearheads because, although it is very hard, it is more readily shaped than stone; edges can be flaked off with comparative ease, especially those of freshly dug pieces, by pressure exerted with a piece of stone or bone. Since it is not chipped by pounding, as stone is, sharper edges are obtained. Use of flint tools defines the Stone Age cultures of the Pleistocene epoch. It was long used with steel for lighting fires and later for setting off the powder in flintlock firearms.

flint Granular variety of quartz (SiO₂) of a fine crystalline structure. It is usually brown or dark grey, although the variety known as chert is a paler grey. It occurs in rounded nodules and is found in chalk or other sedimentary rocks containing calcium carbonate. Of great importance to early humans during the Stone Age, flint flakes when struck a glancing blow, leaving sharp edges appropriate for tools and weapons; two flints struck together produce a spark which can be used to make fire.

flint / flint/ • n. a hard gray rock consisting of nearly pure chert, occurring chiefly as nodules in chalk. ∎  a piece of this stone, esp. as flaked or ground in ancient times to form a tool or weapon. ∎  a piece of flint used with steel to produce an igniting spark, e.g., in a flintlock gun, or (in modern use) a piece of an alloy used similarly, esp. in a cigarette lighter. ∎  used to express how hard and unyielding something or someone is: mean faces with eyes like flints.