Earth's gravity

The density of the rocks composing the crust, an average of less than 2.7, limestone and dolomite, clays, sandstones, granites, porphyries, trachytes, basalts, schists have a specific gravity in most cases significantly lower than 3, only some basalts are slightly higher than this figure, even the lodestone of their relative weight is easier to Earth (4,9 - 5,2), heavy metals exceed his last density. If the masses that make up a significant part of the crust, so easily, it is natural to assume that at great depth is a heavy nucleus, consisting of the metals. When comparing the meteorite with the Earth, we saw that the existence of meteoric iron, and his relationship with igneous boulders Ovifaka in Greenland indicate the presence inside the Earth large amounts of this metal. It may well be that there are rich reserves of precious metals, which are out of all the known bodies have the highest weight.