It's hard to tell from this angle and the lighting isn't helping but it *could* be a Scabos travertine? I'm fairly certain though that it's an "antiqued" or "brushed" finish, which gives the stone a wonderfully warm luster.
For what it's worth, that's a very shoddy installation. Even for a "rustic" feel, there's no joint cohesion, no discernible pattern and the perimeter cuts detract from the beauty of the stone.
Here's a link to a photo which demonstrates the broad range of variegation you can expect to see in Scabos travertine.
http://www.euroitaliastone.com/images/pavers/scabos_travertine.jpg
Best of luck.

Thank you very much for great information! Yes I need as much Luck as I can get! :)

Are your serious?? This isn't Swiss cheese travertine at all. This is a reclaimed antique Limestone. see photos here: http://www.ancientsurfaces.com/Biblos-Stone.html

Just want to compliment you...well done.