flinty

Flinty is an adjective derived from flint, a hard cryptocrystalline form of quartz. In geology and archaeology, flinty describes materials related to or resembling flint. Flint is a variety of chert, composed mainly of microcrystalline silica (chalcedony and quartz). It typically forms as nodules in sedimentary rocks such as chalk or limestone, particularly in Europe. Flint nodules are usually gray to dark gray or black, with a waxy or glassy luster, and they fracture with a characteristic conchoidal break.

Flinty materials are extremely hard and resistant to weathering; they can be struck to produce sharp edges. Historically, flint was widely used to make tools and weapons, and flint-knapping remains a key technique in prehistoric lithic technology. Flint has also been used in building, especially in parts of Europe where flint nodules are embedded in mortared walls, giving distinctive textures.

In addition to its mineral sense, flinty is a figurative descriptor. When applied to a person or attitude, it indicates hardness or stoicism—unyielding, austere, or unsentimental. Phrases such as a "flinty gaze" or "flinty heart" convey this sense.

The word’s etymology traces to Old English flint, from Germanic roots. Modern usage often retains the mineral sense in geology contexts and the figurative sense in literary or descriptive writing.