River Pebbles texture / procedural

Hi everyone! Today i’m trying to create a bunch of river pebbles, no problem with Modelling and physics, but i really can’t find a pebble texture, i’ve also tried to make it procedural, but it looks horrible…
This is my actual scene, nothing special, i’m just exercising.

By the way, do you know why is my gpu rendering that broken? ( i have an AMD R9 290x )

How about this:


I’ll try that, but how about some white pebbles? Like those that you find near a river or in some Zen garden.