Flint nodule. Flint is a variety of microcrystalline or cryptocrystalline quartz. It occurs as nodules and concretionary masses, and less frequently as a layered deposit. It breaks consistently with a conchoidal fracture and was one of the first materials used to make tools by early people. They used it to make cutting tools. This specimen has a diameter of about ten centimeters and comes from the coast of the Baltic Sea, Germany.