Oolite (egg stone) is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Hellenic word òoion for egg. Strictly, oolites consist of ooids of diameter 0.25–2 mm: rocks composed of ooids larger than 2 mm are called pisolites. The term oolith can refer to oolite or individual ooids.
This type of limestone is also found in Indiana in the United States. The town of Oolitic, Indiana was founded for the trade of limestone and bears its name. Quarries in Bedford, Oolitic, and Bloomington contributed the materials for such iconic US landmarks as the Empire State Building and the Pentagon. The Soldiers' and Sailors' Monument in downtown Indianapolis is built almost solely of grey oolitic limestone.
The movie Breaking Away centers around the sons of quarry workers in Bloomington, the home of Indiana University. Almost all of the buildings on the Indiana University campus are built with native oolitic limestone material.
Roggenstein is a term describing a specific type of oolite one in which the cementing matter is argillaceous.