Bluestone

Bluestone is a cultural or commercial name for a number of natural dimension or building stone varieties, including: It is unrelated to human-made blue brick.

The term "bluestone" in Britain is used in a loose sense to cover all of the "foreign," not intrinsic, stones and rock debris at Stonehenge.

The majority of them are believed to have come from the Preseli Hills, about 250 km (150 miles) away in Wales, either through glaciation (glacial erratic theory) or through humans organizing their transportation.

[5] In support of the glacial erratic theory, researchers reporting in 2015 found no firm evidence of quarrying at Rhosyfelin in the Preselis.

[10] Further, no independent evidence has ever been found to support the thesis of long overland or sea transport of Preseli bluestones from Wales to Salisbury Plain.

Bluestone is a very hard material and therefore difficult to work, so it was predominantly used for warehouses, miscellaneous walls, and the foundations of buildings.

However, a number of significant bluestone buildings exist, including the Old Melbourne Gaol, Pentridge Prison, St Patrick's Cathedral, Victoria Barracks, Melbourne Grammar School, Deaf Children Australia and Victorian College for the Deaf, Vision Australia, the Goldsbrough Mort warehouses (Bourke Street) and the Timeball Tower at Williamstown, as well as St Mary's Basilica in Geelong.

Crushed bluestone aggregate, known as "blue metal" (or "bluemetal"), is used extensively in Victoria as railway ballast, as road base, and in making concrete.

The sand-sized grains from which bluestone is constituted were deposited in the Catskill Delta during the Middle to Upper Devonian Period of the Paleozoic Era, approximately 370 to 345 million years ago.

[15] This delta ran in a narrow band from southwest to northeast and today provides the bluestone quarried from the Catskill Mountains and Northeastern Pennsylvania.

It is a limestone formed during the Ordovician Period approximately 450 to 500 million years ago, at the bottom of a relatively shallow ocean that covered what is today Rockingham County, Virginia.

[20] The stone eventually fades from a deep blue to a light grey after prolonged exposure to sun and rain.

When James Madison University was built, the local bluestone was used to construct the buildings because of its high quality and cultural heritage.