Small ceramic stone, made to curve comfortably for your thumb. Rub your thumb over the glazed surface to release tension or anxious feelings, and relax. Rubbing them can also help some with focus. This small ceramic stone fits perfectly in a pocket, or with its nice glaze and design, looks nice even sitting out on a desk or end table. Top is glazed, and bottom is unglazed clay. Calming stone measures approximately 1.5 inch surface, quarter inch thick