Capua Custom Tile & Stone 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.

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

Stair Design / Iron Design looks like this stair sits in a 8' x 12' square foot print... it all depends on ceiling hight

bepsf Any dense hardwood or old-growth softwood is appropriate for staircases.
However, to maintain the proper rise/run of a staircase, you don't just layer on new planks over old - you remove the old and replace with the new.