Several measurements on each rind are taken, and the samples are often re-evaluated after a week for accuracy. Mathematic calculations are made of the sample's translucency at the various powers of magnification of the microscope. The actual measurement of hydration involves using light transmission to determine the amount of hydration, and therefore the relative age of the sample. The prepared slides are observed by means of a microscope to determine the amount of light transmission. These calculations are used to determine the hydration of the sample, which indicates the age of the sample.
Obsidian hydration is a very advantageous method when identifying the relative age of an artifact.
OH can also be beneficial in finding out the seismic history of an area. References Hamilton, Jeff. Obsidian Hydration Analysis Service . Pacific Internet, 1996. Obsidian Hydration Analysis Service .