Orbiculite

(Orbicular Granite )  Orbicular granite (also known as orbicular rock or orbiculite) is an uncommon plutonic rock type which is usually granitic in composition.

These rocks have unique appearance due to orbicules - concentrically layered, spheroidal structures, probably formed through nucleation around a grain in a cooling magma chamber. 

Almost a third of known orbicular rock occurrences are from Finland. The occurrences are usually very small. 

In New Zealand scattered boulders have been found, this example is from Western Australia.

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