Flint is a type of sedimentary ROCK that is composed of quartz and other minerals. It is often found in the form of nodules or chunks, and has been used by humans for thousands of years. The term 'flint' can refer to several different types of rocks, including silex (5 letters), STONE (5 letters), ROCK (4 letters), chert (5 letters), and firestone (9 letters). These rocks are all similar in composition and have been used for various purposes, such as tool-making and fire-starting.