This chapter starts by describing how a sedimentary rock, with a structure consisting of microscopic quartz crystals that was formed millions of years ago, enabled the creation of our first engineered materials. Hunting and butchering meat using sharp hard-wearing flint tools was key to our evolutionary success. As flintknappers were shaping tools that were more and more refined, flint found additional uses as a means to start a fire, an application that would eventually lead to a new type of deadly weapon, the flintlock. Even with the increasing use of metals with their better durability and ease of shaping, flint remained an important material over an enormous period of history.