Randy Bolt has a passion for rocks. Well, not just rocks, but gems and minerals too. He's a historic guide at California's Mining and Mineral Museum in Mariposa.
He can tell you about the state's official gemstone, "which most people have never even heard of, which is actually one of the rarest gems in the world, it's called Benitoite, named after San Benito Creek."
Or he can tell you about the history of the world-famous nugget from the California Gold Rush that is nearly the size of a basketball.
