From Academic Kids
A microlith is a small stone tool, typically knapped of flint or chert. Microliths were either produced from small blades (microblades) or made by snapping normal big blades in a controlled manner, which leaves a very typical piece of waste (microburin). The latter type of microliths are called geometric microliths. They can be formed as various kinds of triangles, lunate shaped, trapezes etc. The shape of the microlith can be used for dating. Some types of microliths, like trapezes, were used in the Neolithic as well (Linearbandkeramic, Funnelbeaker culture). Microliths were produced during the middle stone age (Mesolithic), in a period which is in some areas denoted as the epipalaeolithic. They were probably used as barbs on arrows, spears and other composite tools.
They are typically 1 cm long and .5 cm wide when finished.