Dated at 9000BC, the oldest obsidian (volcanic glass) bracelet comes from Turkey, the site of Asikli Hoyuk.
The bracelet is almost perfectly regular. The symmetry of the central annular ridge is extremely precise, to the nearest degree and nearest hundred micrometers. This suggests that the artisans of the time used models to control its shape when it was being made. The surface finish of the bracelet (which is very regular, resembling a mirror) required the use of complex polishing techniques capable of obtaining a nanometer-scale surface quality worthy of today’s telescope lenses.