The issue of air pockets in travertine has come up again, and since it has been a long time since I addressed it, I thought I would mention it again. Because of how travertine is formed in nature over the years, it has holes. Some larger than others but all travertine will have holes. In most cases these holes are filled with a resin or a cement filling. Should that fill come out, it can always be replaced with a matching grout.
But what happens when a new hole appears? This is not uncommon and it does not reflect a poor quality product. What happens is over time, one of those holes (or air pockets) that resides just below the surface opens up. The general wear or a poke with a heel or even a dog’s paw can remove the thin layer of stone that covered that hole. It looks like this:
To repair a hole of this nature, simply find a grout with a color match you are happy with and grout the hole.