Teepee Canyon AGATE rough large preformed shaped piece South Dakota. This is a large chunk that has been partially shaped down to prepare it for polishing as a specimen. it is not finished yet. weighs _____ and measures about ________________. Fantastic white, yellow, oranges and red patterns in this one, and one side has a small crystalline area. Teepee Canyon is one of the the original host rock sources where the alluvial Fairburn agates found on the grasslands originated from and traveled by erosion and alluvial action. These are sometimes called Hills Agates or Black Hills Fairburns.