Bluestone Co.

Bluestone is a cultural or commercial name for a number of dimension or building stone varieties, including:
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. It is a "convenience" label rather than a geological term, since at least 46 different rock types are represented. One of the most common rocks in the assemblage is known as Preseli Spotted Dolerite—a chemically altered igneous rock... plus