1. Orbicular Diorite

    “The spectacular circles in this rock are sections through spherical structures formed by the crystallization of layers of different minerals around tiny cores. The rock crystallized from molten magma, but exactly how these structures are produced is not clear - several different theories have been suggested. Cut and polished, the rock makes a spectacular building stone.”

    From the Natural History Museum in London

    Source: Patternbase

    (via patternbase)