That is a stone from a Bigfoot pinky ring. Highly prized by them as heirlooms and worn as a sign of their particular clan; not unlike the tartan kilts of Scottish Highlander history. There are some that say the Bigfoot community of today has some Highlander blood in its veins as well as some Canadian and Amish. The same people also say that Jason Werth of the Washington National is actually a small-ish Bigfoot. I believe he does not wear his clan pinky ring as part of his "cover story".
Well, that's what I heard.