Thirstystone 4-Pack Natural White Marble Coasters with Gold Edges. Natural White Marble is a beautiful and practical option for protecting your surfaces while also adding a touch of elegance to your home. The unique patterns of the stone make each coaster a one-of-a-kind piece. Marble’s natural properties make it heat tolerant and water repellant. Natural Marble is made of metamorphic rock which makes it a durable material that can withstand wear and tear from daily use. Each Coaster measures 4" x 4" Square