What is a common rock found in Washington D.C.?

Question

What is a common rock found in Washington D.C.? Or what is the state rock?

Answer 1

Well, if you count the rocks that the buildings are made of the most common rock type in DC is granite followed by marble (metamorphosed limestone). There are actually some interesting tours called the geology of DC's buildings or something like that. Not counting the buildings, the most common rocks would probably be the metamorphic rocks of the Piedmont and Blue Ridge provinces. Here's an excerpt from a good site that talks about the geology of the Washington DC area:

Washington's Geologic Setting
Metropolitan Washington incorporates parts of four physiographic provinces -- areas in which the rocks and topography are similar but differ considerably from those of the neighboring provinces. From east to west, these provinces are the Coastal Plain, the Piedmont, the Triassic Lowland, and the Blue Ridge. In addition, the area on the Mall south of the Lincoln Memorial and Washington Monument to the Potomac River was originally swampland, which was reclaimed by filling it with material dredged from farther down the river.

The Atlantic Coastal Plain province borders the Atlantic Ocean and consists of gravel, sand, silt, clay, and marl.

The Piedmont Plateau province lies west of the Coastal Plain. The Piedmont rocks in and near Washington, D.C., are crystalline metamorphic rocks that are quite hard and resist weathering; they contain veins of quartz and pegmatite and in many places have been intruded by igneous rock (formed from molten rock from inside the Earth). These crystalline rocks can be seen most easily in valleys where the soil cover has been stripped away by erosion. Most of the crystalline rocks on the uplands were deposited about 550-600 million years ago; over the ages, they have weathered to saprolite, a porous, spongy, red-brown clay-rich material, as much as 200 feet thick. The final product of weathering, seen near the surface throughout much of the Piedmont, is a sticky clay, generally having a reddish color.
The rocks of the Triassic Lowland province, deposited about 200 million years ago, are red shales and red and gray sandstones and conglomerates, which weather to a reddish soil. Near Washington these sedimentary rocks are as much as 5,000 feet thick. In some places, they have been intruded by trap rock (resistant fine-grained igneous rock). At the western edge of the Triassic Lowland is a series of alluvial fans that mark the mouths of ancient rivers. These deposits are made up of rounded to angular masses of limestone, quartz, and quartzite, which range in size from sand grains to boulders as much as 1 foot in diameter, that are cemented by calcite.

The Blue Ridge province, lying west of the Triassic Lowland, is a region of north- and northeast-trending valleys and ridges underlain by folded metamorphic and igneous rocks that were formed more than 500 million years ago. Near Washington, the rocks consist predominantly of granite, greenstone (metamorphosed by great heat and pressure from basaltic lava flows), and quartzite. Sharp north-trending ridges, formed by steeply dipping quartzite that resists weathering, rise more than 1,000 feet above sea level.

Answer 2

a common rock found around washington DC is a very deceptive question. You have both sedimentary and metamorphic rocks that are very common around DC. A type of rock that is found in and around the potomac river is called greywacke which could is a more specific name for a sand stone. Some other kinds of rocks there are schist, mable, granite, biotite, muscovite, K-Feldspar, ect. So pick your rock, and that would be about common there!

Answer 3

yup crack and its on every street corner

Answer 4

crack