The Barton mine on Gore Mountain worked the largest garnet crystals on Earth, deep-red almandine so hard it was sold as industrial abrasive. Garnet is the New York state gem, and the old North River mine runs public garnet-mine tours and a collecting site in season, up in the southern Adirondacks.
Garnet (NY state gem)
See it on the map
Other places on the map within a couple of hours.
