Potomac Bluestone

The Official Stone of Washington, DC

Potomac Bluestone is a durable metamorphic gneiss that forms part of the ancient geological foundation of the Washington, DC metropolitan region. Created hundreds of millions of years ago through intense heat and pressure, this distinctive blue-gray stone is found throughout the Piedmont landscape surrounding the nation's capital. Natural outcrops can be seen in Rock Creek Park, along the Potomac River Gorge, near Great Falls Park, and throughout portions of Montgomery County, Maryland, where the region's underlying bedrock is exposed.

Historically, Potomac Bluestone was used in foundations, canal structures, bridges, curbing, and other early construction projects throughout Washington, DC. Its strength, durability, and local significance led to its designation as the official stone of Washington, DC. Unlike Pennsylvania bluestone, which is a sedimentary sandstone that naturally splits into flat slabs, Potomac Bluestone is a dense crystalline metamorphic rock that fractures into strong, block-like forms.

Each specimen is unique. Because Potomac Bluestone is a natural stone formed by geological processes over hundreds of millions of years, no two pieces are exactly alike. Variations in color, mineral composition, texture, shape, size, and banding patterns are natural characteristics of the stone and help make every specimen one of a kind. The stone pictured is representative of the type of Potomac Bluestone offered for sale, but the specimen you receive will have its own distinctive appearance and character.

Own a genuine piece of the geological heritage that helped shape the landscape, architecture, and history of the nation's capital.