than bridgmanite, becoming stable at approximately 500 km, and remains stable throughout the lower mantle. Abundance Bridgmanite is the most abundant mineral in the mantle. The proportions of bridgmanite and calcium perovskite depends on the overall lithology and bulk composition. In pyrolitic and harzburgitic lithogies, bridgmanite constitutes around 80% of the mineral assemblage, and calcium perovskite < 10%. In an eclogitic lithology, bridgmanite and calcium perovskite comprise ~30% each. Presence in diamonds Calcium silicate perovskite has been identified at Earth's surface as inclusions in diamonds. The diamonds are formed under high pressure deep in the mantle. With the great mechanical strength of the diamonds a large part of this pressure is retained inside the lattice, enabling inclusions such as the calcium silicate to be preserved in high-pressure form. Deformation Experimental deformation of polycrystalline under the conditions of the uppermost part of the lower mantle suggests that silicate perovskite deforms by a dislocation creep mechanism. This may help explain the observed seismic anisotropy in the mantle. See also Ringwoodite References External links Petrology Silicate minerals Perovskites High pressure science