It is built of knapped flint with stone dressings. Flint and chert are the most commonly knapped materials and are compact cryptocrystalline quartz. The walls are of knapped flint with some brick and stonework. Peartree has a small Victorian extension faced with galleted knapped flint. It is built in four stages, of knapped flint and stone with rare clasping buttresses. In English flushwork, limestone and dark knapped flint are used. He regains consciousness and kills the Roller using a knife knapped from a flint-like rock. Each letter is crowned, and set in knapped flints. Like obsidian, it was knapped and used to make tools during the Pleistocene. Early humans lived and knapped flake tools inside the Tabon Cave. The plinth is formed of unusual knapped stones.