I took two tiles (above), that are from different sets. The one on the left feels much like a ceramic and the one of the right feels like a hard plastic.  On the sidewalk, I hit them each a couple of times with a hammer,  both lost small chunks.  Then I took a lighter and held it to the end...

My conclusion is that the bamboo is real, the white part is a brittle white plastic. Both got soft after heating.