Oldest Obsidian Bracelet Reveals Amazing Craftsmen's Skills in the Eighth Millennium BC: Dated to 7500 BC, the Obsidian Bracelet Studied by the Researchers is Quite Unique.

""Dated to 7500 BC, the obsidian bracelet studied by the researchers is unique. It is the earliest evidence of obsidian working, which only reached its peak in the seventh and sixth millennia BC with the production of all kinds of ornamental objects, including mirrors and vessels. It has a complex shape and a remarkable central annular ridge, and is 10 cm in diameter and 3.3 cm wide. Discovered in 1995 at the exceptional site of Asıklı Höyük in Turkey and displayed ever since at the Aksaray Archeological Museum, the ring was studied in 2009, after Mihriban Özbasaran, Professor at the University of Istanbul's Department of Prehistory, resumed excavations.

Laurence Astruc, a CNRS researcher and her colleagues analyzed the bracelet using extremely powerful computer technologies developed by LTDS researchers Hassan Zahouani (ENISE) and Roberto Vargiolu (ECL). Developed for industry in order to characterize the 'orange peel effect' on painted car bodywork, these methods, known as multi-scale tribological analysis, have been adapted for the study of micro-topographic features on archeological artefacts. They seek to identify every single operation performed on the surface of these objects.

This process has revealed that the bracelet was made using highly specialized manufacturing techniques. The analyses carried out showed that the bracelet was almost perfectly regular. The symmetry of the central annular ridge is extremely precise, to the nearest degree and nearest hundred micrometers."" 

http://www.physorg.com/news/2011-12-oldest-obsidian-bracelet-reveals-amazing.html