The Quartz Mountains are an extension of the Wichita Mountains in the far southwestern part of the state of Oklahoma. According to the Encyclopedia of Oklahoma History and Culture, the range was originally formed about 550 million years ago as a "failed continental rift". It was uplifted about 300 million years ago and has since weathered into its current condition. The unique geography provides cover for the most northerly natural population of the Texas live oak, quercus fusiformis. This rare oak is generally regarded as the most cold hardy evergreen oak.