Acid Rain and Our Nation's Capital: A Guide to Effects on Buildings and Monuments

by E. S. McGee

★ U.S. Government Printing Office: 1995-394-904

What Type of Rock is It?

Look at the overall appearance of the stone in the building. Observe the color, texture, and structure of the stone.

Does the stone look evenly colored, with an even texture? YES ⇒ Look at the grains up close. Do you see fossil fragments (bits of shells or skeletons)? YES ⇒ LIMESTONE NO ⇒ Are the grains rounded, like sand on the beach? YES ⇒ SANDSTONE NO ⇒ {same as next line} NO ⇒ Do you see streaks or clouds of color in a mostly white stone? YES ⇒ MARBLE NO ⇒ Look at the grains up close. Do you see a mixture of colors (black, white, gray, maybe pink or red)? YES ⇒ GRANITE NO ⇒ MARBLE

Some of these stones may have layers that were the original beds that formed the stones.

LIMESTONE

SANDSTONE

The grains in these rocks may look like crystals that fit together like jigsaw puzzle pieces.