No doubt that’s catlinite. The earliest Indian smoking pipes date to the late archaic. By the middle woodland Hopewell time period, around 200 AD, catlinite was utilized for platform pipes. From then on its use picked up even more. Mississippians used it extensively and use continued into modern times. It’s easy to work but it is messy! The pink dust from grinding spreads everywhere. My wife raised hell when I tracked it on my shoes.😄