Fluorite Specimen Bulk $8 Per Pound Rough Rock for Tumbling. $8.00. Chevron Amethyst Rough Stones Bulk $6.00 Per Pound Mexico. $6.00. Black Moonstone Specimens Bulk Rough Rock $8.00 Per Pound. $8.00. Peacock Pyrite Rock Specimen $6.50 Per Pound Bulk Rocks. $6.50. Unpolished Emerald Rock Specimen $9.00 Per Pound Sold In Bulk. Rock Tumble. Experts in Stone Tumblers and Rock Tumblers used for tumbling and polishing rough rock, stones and pebbles, including those found on the beach, and glass Our high quality British Made lapidary machines give a professional finish to your samples.