Schorl (black tourmaline). October birthstone.
Crystals of deep black tourmaline, or schorl, from New York. The specimen is mounted on a gold coloured base. Tourmaline is an October birthstone.
3/8 inch (0.95 cm) wide, 3/8 inch (0.95 cm) deep and 7/16 inch (1.1 cm) tall.