Approx. 20mm round cabochons, made of synthetic rhodochrosite.
Natural white magnesite is cool and smooth to the touch. This relatively soft and porous stone is often stabilized with a clear bonding agent to make the surface smoother, harder and more resistant to scratches. These magnesite cabochons are turquoise-dyed and treated to enhance the durability.
Note: the image gives you a good general idea of what the cabochon looks like, but colors and patterns of natural stones may vary from lot to lot.