Aegean Tile 4 Pack Natural Travertine Absorbent Stone Coasters. The Natural Travertine Stone is mined in the mountains of Turkey. We import this Natural Travertine Stone then Manufacture the Coasters here in the USA. Travertine Stone is a form of terrestrial limestone that is deposited around mineral springs. Travertine Stone is known to be very durable and absorbent. Travertine Stone has a distinctive striking appearance. Coasters have a cork backing which protects your surfaces from scratches and stains. Artistic designs are printed on the surface of each coaster. These attractive Coasters add elegance and distinction to your space. Because this is natural stone marble, the coasters may vary is shape and color. The Coasters are made for long lasting use. Each Coaster measures 4” x 4” x 0.43”.