Orbicular granite (also known as orbicular rock or orbiculite) is an uncommon plutonic rock type which is usually granitic in composition. These rocks have a unique appearance due to orbicules - concentrically layered, spheroidal structures, probably formed through nucleation around a grain in a cooling magma chamber. Almost one third of known orbicular rock occurrences are from Finland. The occurrences are usually very small.
Read more about Orbicular Granite: South African Occurrence, Places With Orbicular Granites
Famous quotes containing the word granite:
“Hell is paved with great granite blocks hewn from the hearts of those who said, “I can do no other.””
—Heywood Broun (1888–1939)