Sickle-gloss, or sickle gloss, is a silica residue found on blades suggesting that they have been used to cut the silica-rich stems of cereals and forming an indirect proof for incipient agriculture. The first documented appearance of sickle-gloss is found on flint knapped blades in the Natufian culture (12,500 to 9500 BC) in the Middle East, primarily in Israel.