Granite

graniet began forming 1.500 million years ago, in the volcanic age 57:7.5

The lava layers of the earth’s crust, when cooled, form granite. The average density of Urantia is a little more than five and one-half times that of water; the density of granite is less than three times that of water. The earth’s core is twelve times as dense as water. 58:5.5