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:
“I make myself this time
Of wood or granite or lime
A wall too hard for crime
Either to breach or climb....”
—Robert Frost (1874–1963)