ggmoorman,
These stones can be found at a few places - these are from porcelanosa - BAIA STONE NEGRO- 12" X 12". Thank you for the question... Good luck and let me know if I can help you further,
Michael

ANN SACKS carries river stones that look just like that, they're called Bali: http://www.annsacks.com/onlinecatalog/program.jsp?cat=268804&coll=278204&prg=1040204

No the river stones are not from Ann Sacks..see my previous response. http://www.porcelanosa-usa.com/home/products/mosaics.aspx/d=13051

Can you tell me what colour grout you used?

lauraanneronin.
Regardless of the grout we selected this is the process you should do:
Have the contractor provide you a full range of the grout colors available by the appropriate grout manufacturer (e.g. mapei). It is then always important to have the contractor mock up on a board that is 2' x 2' minimum, a few color grout options ( you have selected) with the stone/tile you are using , look at it in the room with the lighting that will be used- select the one you think works best based on the mock up. There is debate about using custom grout colors, I think there is a great enough range that you should be able to use standard colors from the grout manufacturers. Good luck,
Michael