The buildings shown above are the two oldest surviving buildings in the town of Rockmart, in northwest Georgia (U.S.A.). The upper is the old town store, and the lower is the Presbyterian Church.
 Both structures are built of slate, a fine-grained metamorphic rock with a well-developed cleavage or tendency to split along flat planes. The result is a platey stone, so that many of the stones visible in these buildings give an elongate aspect. One piece at the upper right of the image below is turned perpendicular to the others, so that a light gray cleavage plane can be seen, rather than the dark gray broken surfaces visible across the rest of the image.
 

           

            The slate buildings are appropriate for Rockmart, because the town is surrounded by outcrops and quarries of the Rockmart Slate. Slate has been quarried near Rockmart since 1850, and it is still quarried by the Rockmart Slate Corporation. Rockmart slate has been used widely as a buidling and landscaping stone, and it has been used as far away as London, England. It is also used as a light-weight aggregate in concrete where weight is critical, and so was for example used in the Golden Gate Bridge. The area's production of slate gave Rockmart its name when the town was chartered in 1872.