Moonstones in Montana, amethyst and emeralds in North Carolina, garnet and quartz in upstate New York. At pay-to-dig mines around the United States, visitors can paw through piles of mine tailings to ...

DILLON, Mont. — Molten granite formed the Pioneer Mountain Range in southwest Montana about 72-million years ago. As the granite cooled, water carried quartz and other minerals through the rocks and ...