I believe gold is the answer, one of the heaviest metals capable of creating a core for a new planet, possibly the 10th, unnamed of planet. i dont know much about astonomy, but i believe two pyramid tops the same size made of a heavy metal could be put into orbit with both 60 degree tips used for "poles" and the rest could be left out in space with a little ice added for life forms to become. the core would be strategically plced in front of comets which would become the dirt and add to the crust until the planet got close enough to the sun for some of the ice to melt and to mix with the dust of the comets forming a new planet after a few hundred thousand years until the dust settles and the planet becomes like mars, a barren red planet, or the main colors of the lightest material on the planet, most likely ice and parts of the comets, creating the top "soil" layer. Afterwards life forms begin to take over and later it gets so crowded they have to move on to the next planet.