Ironwood Builders Yep. Looks like white Portland blend custom concrete. Look up Twisted Minds Design's ongoing concrete forum. Search discussions and keyword concrete counters and see if you can find it! Best of luck!
nFORMAL design Actually, it looks like grey concrete with titanium white oxide pigment. That give it the "silvery grey" look. To get bright white, you have to use white portland cement, white aggregates and white pigment. Otherwise, it will be "off white". Also, don't have it polished too much or the buff sand color will show through. However, if you don't want bright white, there are many possibilities.
Twisted Minds Custom Designs Ironwood, thanks for the alert to this link. Batool, it's a little hard to decipher from the picture, but It could be either a preformed concrete countertop, or a concrete overlay placed over exisitng countertop, or even a poured in place countertop. I don't know your location, but if you can find a local concrete artisan and bring your ideas for your countertops, you can work together to design the pieces you desire. One of the beautiful aspects of concrete is it can be colored, styled, cast, and designed in an almost endless array of choices. I'll include the link to the FAQ's page I created, please read and if you have any additional questions feel free to ask, I'd be happy to answer.
http://www.houzz.com/discussions/346684/Concrete-Countertops-FAQ-s-by-Twisted-Minds