The "stones" on these clear glass dishes are glass! Several layers of glass are fused into rounded stone shapes, then painted and fired again to look like polished river stones. Honestly, you cannot tell the difference! The plates measure approximately 7.5" x 4.5", and can be used as sushi dishes or collectibles trays. Your choice of chopsticks or a wooden spreader included, please indicate preference in notes. Dishwasher safe but to maintain the glossy finish of the stones, hand-washing is recommended.