From the manufacturer's website:
Syndecrete is a cementitious composite using natural minerals and recycled materials. It as a solid surfacing material that is less than half the weight and twice the compressive strength of ordinary concrete.
What that means for you and me is that Syndecrete—or more properly "syndeCRETE"—is available in a variety of colors and textures. It's sort of like a concrete Dairy Queen "Blizzard," except instead of a Heath Bars and coffee you get abalone, glass, or wood chips.
Lots more colors and information is available on the Syndecrete page.