The concentric, round, inclusive bodies—called orbicules—form in cooling magma chambers. A phenomenon called rhythmic crystallization, in which different minerals crystallize in concentric layers, produces this distinctive structure.
Show lessRead more
Details
Title: Orbicular Diorite
Location: Corsica, France, Europe
Type: MIneral
Rights: This image was obtained from the Smithsonian Institution. The image or its contents may be protected by international copyright laws. http://www.si.edu/termsofuse