Buckingham Slate refers to a specific type of slate

Slate

Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering...

 quarried near Arvonia in Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

. The Buckingham Slate Company is the only active quarry and manufacturer of slate in Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

. Buckingham slate has a distinct blue/black color and glistens due to its high Mica

Mica

The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition...

 content.

Buckingham slate roofs can be found on many Federal buildings and national landmarks, including Ford's Theatre

Ford's Theatre

Ford's Theatre is a historic theater in Washington, D.C., used for various stage performances beginning in the 1860s. It is also the site of the assassination of U.S. President Abraham Lincoln on April 14, 1865...

, the Smithsonian Institution Building

Smithsonian Institution Building

The Smithsonian Castle, located on the National Mall in Washington, D.C. behind the National Museum of African Art, houses the Smithsonian Institution's administrative offices and information center...

, the University of Virginia

University of Virginia

The University of Virginia is a public research university located in Charlottesville, Virginia, United States, founded by Thomas Jefferson...

, and Tuckahoe Plantation

Tuckahoe Plantation

Tuckahoe, also known as Tuckahoe Plantation, is located on Route 650 near Manakin, Virginia overlapping both Goochland and Henrico counties...

, (the boyhood home of Thomas Jefferson

Thomas Jefferson

Thomas Jefferson was the principal author of the United States Declaration of Independence and the Statute of Virginia for Religious Freedom , the third President of the United States and founder of the University of Virginia...

).