What Kind Of Rock Is This?

Common rock smoothed by stream or ocean activity?

Why do you ask? Is there something you think is unusual about it?

You found it outside where? What country, state, etc. Is the rock wet in the photo or is it naturally shiny? The photo looks like the sort of thing found on the beach in Fla. Fossil coral etc.

I found it in washington. It's wet. I'm wondering as to the type of rock (e.g. basalt, gabbro...)

Farmerman would know better than I, but I would say it's probably impossible to tell without exposing an unpolished surface (by cracking it open). And even then it may not be obvious without doing some chemical tests.

Crack it like Ros suggests. If it's glassy it might be volcanic glass. If smooth but not 'specially glassy it might be jasper or basalt. If of non-uniform composition, might be conglomerate but doesn't look that way. Wild guessinbg

Drip on it a little dilute acid. If it fizzes it might be/contain limestone

http://en.wikipedia.org/wiki/List_of_rock_types