Topo Coasters represent the real topography of our favorite places. The elevation changes are illustrated with layers of cork. Cork is an amazing natural material. It is absorbent yet dries quickly. It grows as bark on the Quercus Suber, or Cork Oak, tree. Best of all, harvesting the cork does not harm the tree. The back of each coaster is plywood engraved with the geographic coordinates for the location depicted on the front.