Dashington trade; Flat Black Marbles (5 Pound Bag), Glossy Finish, for Vase Filler, Table Scatter, Aquarium Decor Dashingtons High Quality Decorative Black Glass Gems. Perfect for Aquarium and Floral Use. 5lb Bag contains approximately 400-500 marbles. Decorative and Smooth Finish. Size Approximately: 3/4"