Natural pebble touchstone from Izmir, western Turkey, 1986

Natural pebble touchstone purchased in the bazaar in Izmir in Western Turkey in July /August 1986 by Prof Andrew Ramage. The gold streaks on the surface were applied by Dr W.A. Oddy during gold assaying tests. Previous identifier: 1986-7

Touchstones are fine-grained siliceous stones, on whose abrasive surface a gold sample undergoing checks for purity would be rubbed. A streak of gold would be left on the stone’s surface, which could be compared against gold of known quality, to establish the sample’s purity. Touchstones were the main means of assaying the quality of gold throughout history, but remain in use today.