Geological and astronomical observations on "lava world" of the rocky planet, with additional theoretical interpretation of Moon's crustal formation, bring up to the occurrence of magma ocean and lava ponds, which inherits accretion energy of rocky planetesimal and evolves with subsequent energy releases. Hemispherical or global oceans of silicate melt could be a widespread lava phase after rocky planet accretion as well as large impact, and could persist on planets on orbits around other stars for various time scales. The processes of magma ocean formation and solidification change the phases, cause element segregations, and strongly affect the earliest compositional differentiation and volatile content of the terrestrial planets.

Of this process, crystallization and subsequent paritcle motion are the key to understand the dynamics and layering.  During such period, magma ocean meets the diluted suspension approximation; thus the internal temperature is between liquidus and critical temperature for diluted suspension of crystals.