text: Obsidian hydration dating was introduced in 1960 by Irving Friedman and Robert Smith of the U.S. Geological Survey. Their initial work focused on obsidians from archaeological sites in western North America.
  The use of Secondary ion mass spectrometry (SIMS) in the measurement of obsidian hydration dating was introduced by two independent research teams in 2002.
  Today the technique is applied extensively by archaeologists to date prehistoric sites and sites from prehistory in California  and the Great Basin of North America.  It has also been applied in South America, the Middle East, the Pacific Islands, including New Zealand and Mediterranean Basin.