Montana Dryhead agate is found in an ancient sea bead and is considered to be a sedimentary type agate. The Dryhead agate is a banded nodule type of agate. The predominant coloring in the bands is yellow, orange, and white. Other colors that may be found are blue, purple and pinks. The Dryhead agate site is located in the Bighorn Canyon area of Montana, just north of the Wyoming border. One of the Native hunting rituals was to stack the heads from buffalo kills to dry and bleach in the sun. These stacks of bleached skulls resulted in this area being called Dryhead.