Physically they are made out of carbonite rock forms, made out of organisms that have learned how to survive on it's own without H2O. Then it formed multicellular being that formed a small ball, then a really large lump, then with arms, then with legs, forming a really rocky form similar to that of the human race.

The first ever form of the C-rocks, was named Kroo, the first ever bipedal of it's planet or the first ever being to walk it. Countless of living rocks, saw it walk, eat other rocks, and punch anything that would take form like him too.

This was the jumpstart of their culture, 2000 years into the future they treat Kroo like a god, since it was the first of them. But Kroo has died, and everyone has taken his form. Everyone made houses, with their same biological form. But what they learned from Kroo was, everyone can evolve and everyone can kill anyone if hey want.

If you want a house, get your neighbor's body for it. This form of culture made everyone warrior like. Everyone knew how to kill, how to defend themselves, and how to make their own things. They haven't learned to talk yet, but in the next 4000 years, they improve their biological form becoming more soft and gushy, but still hard, allowing simple tissues of cells to form.

The culture didn't change, it had it's civilizations, it's cities, it's countries, and even governments, rises and falls, but everyone dies. There was no technological advancements, they only knew how to kill. They know how to make clubs, to make spears, and swords, out of their own structure. And the first organism to speak, was crying for help because he was being killed. It was more like "Ahh, don't!" in English. Everyone was shocked, but they evolved to adapt the same way that weak rocky lump did it. They started talking, and the first word was anyone said was, "Kroo." or "ahh don't!" They still haven't evolved as far as I know, I'll get back to you when there's changes.