Go stones Set of 10 15 white stones, 15 black stones Material: I think it's probably plastic. I apologize if I'm mistaken. Size (cm): Diameter 2.14, Thickness 0.72 These are average values, so there may be slight variations between individual stones. Please forgive any errors as these were measured by an amateur. Please note that the color of the actual product may differ slightly from the photos depending on your smartphone or other device. These are used items, so they may include minor scratches, light stains, and signs of use. However, there is no major damage, so the condition of the product is rated as "no noticeable scratches or stains." I have checked carefully, but please forgive any oversights or omissions in the photos as this is an amateur inspection. Please consider purchasing only if you understand and agree with the product description.