The figure of the Earth and effect on gravitational force Equatorial bulge - 21 km larger than the polar radius. The differences are called gravity anomalies.
Anomalies track excess or deficiency of mass.
Depth to the Moho deduced by seismic data show that crust is thicker under mountains. Building blocks of rocks. Number of atoms of a given element in a molecule is indicated by subscript. Compounds - charge neutral, by a balanced combination of anions and cations. This silicate anion is the basic building structure for silicates, the most common rock forming minerals.