While there's a chance it is marble, my money is on travertine. The consistent fairly straight lines are the clue. Travertine is very porous so it requires heavy and/or very regular sealing, but the look is amazing. Check out a travertine bathroom below for comparison.
Horizon - Residential & Commercial Builders
Evan U.
Related Discussions
Kitchen counter top replacement for sale
Q
'Fresh Concrete' alternatives for lower maintenance kitchen counter
Q
Dilemma: Gray Tile Flooring and Piatra Gray Counter don't go together
Q
Colonial White Granite kitchen countertops
Q