It's nearly a sure bet that everybody who ever made stone tools and knew about obsidian and where to find it, used it.
Temperature fluctuates daily, seasonally and over longer time scales in every region on the planet.Under laboratory conditions, rind formation can be modelled as a diffusion process, this allows for the estimation of EHT-dependent hydration rates.EHT (effective hydration temperature) can be measured using surrounding temperature cells (Lee.1969) or can be extrapolated from temperature histories (Rogers.2007).But, since the amount of water within obsidian can vary even within obsidian nodules from a single source, that content can significantly affect age estimates. Long published the first study, the results of an experimental hydration of obsidian from the Valles Mountains of New Mexico.Obsidian's measurable rate of rind growth has been recognized since the 1960s. Since that time, significant advancement in the recognized impacts of water vapor, temperature and glass chemistry has been undertaken, identifying and accounting for much of the variation, creating higher resolution techniques to measure the rind and define the diffusion profile, and invent and improved new models for EFH and studies on the mechanism of diffusion. "Obsidian Hydration - An Inexpensive, but Problematic Dating Technique." Thought Co.
The effects of variation in water vapor pressure in the climate where an obsidian artifact has been found have not been studied as intensively as the effects of temperature.