Limestone and Travertine are both formed by the settling of plants, seashells, sand, animals and mud on the sea beds. You see fossils on both of these stone.
Usually, Travertine has got holes but sometimes it can be filled with an epoxy resin.
At this point, it can be difficult to distinguish the finished travertine product from limestone. Travertine is generally used for floors, walls, counter-tops and for outside as cladding and pavement. Unfilled travertine is also quite beautiful, and is often seen as exterior surfaces of buildings. Limestone (usually beige) is suitable for bathrooms, fireplaces, counters and floors.