The maximum attainable pressure in a multi-anvil type of high-pressure apparatus (MAA) is limited to about 27 GPa when using tungsten carbide (WC) as anvil material. Recently a remarkable innovation has been made for the MAA by adopting sintered diamond (SD) as anvil material. So far pressures up to 49 GPa has been confirmed in SD anvil assembly without any reduction of the specimen volume. Therefore, phase equilibrium and melting experiments of Earth materials have been extended to conditions deep into the lower mantle. The results will substantially advance our understanding of the structure of the lower mantle and the state of Earth early in its history.