What unique geological bloom flowers only in Oklahoma?

A few months after How Curious host/producer Rachel Hopkin moved to Oklahoma, she was given a barite rose rock by two of her dear neighbors. It came in a box with a short text attached which stated that to hold it was “literally like holding a quarter billion years of history in the palm of your hand.” That gift provided the impetus for this episode, in which Rachel finds out more about this geological bloom and why it's unique to just one part of the Sooner state.