The properties of the main lower-mantle phase appear to be more complex than expected. The common procedure of using the properties of the simplified MgSiO₃ (and [Mg,Fe]SiO₃) composition for direct analogy to the Al-bearing (Mg,Fe)SiO₃ lower-mantle perovskite can lead to significant misinterpretations. The presence of Al and Fe affects the equation of state, the defect population, the ability of this phase to insert minor and trace elements, and the transport properties, etc. Some difficulties remain for the quantitative determination of these effects because of two main reasons: many experimental techniques are ineffective because silicate perovskite is...