The Lincoln Memorial, dedicated in 1922, is made of marble from
Colorado. This building has few alteration crusts, in part because it
receives regular cleaning and in part because of the design of the
building. Except for the features around the entablature (the edge of
the roof), there are few sheltered areas where alteration crusts can
accumulate. With the aid of binoculars, you can see some alteration
crusts along the underside of the roof overhang; in these places the
marble is very badly crumbled under the alteration crusts. Some columns
show preferential weathering or loss of inclusions, but some of this
damage might be from graffiti removal. The most visible dissolution
feature is sugaring, where the stone has lost its polish and the surface
now feels rough. Visitors have affected this popular memorial too;
several of the columns, especially the limestone columns inside the
chamber, show darkening and rounding of edges where visitors have
touched them over the years.
One interesting feature at the Lincoln Memorial is differences in stone
condition that must come from variations in the stone. At several places
around the outside of the memorial, adjacent blocks of marble show very
different surface roughness. Since the blocks of stone have the same
orientation with respect to wind, rain, and pollution, the difference in
condition cannot be due to exposure and must be related to basic
characteristics in the stone that was used.
[Illustration: The Lincoln Memorial is made of marble and was
dedicated in 1922.]
[Illustration: Under the roof overhang is one of the few places at
the Lincoln Memorial where alteration crusts have developed on the
marble.]
[Illustration: Some columns at the Lincoln Memorial have flattened
chalky areas where inclusions have weathered differently from the
surrounding calcite.]
[Illustration: The marble guttae on the roof overhang are crumbling
and falling apart underneath blackened alteration crusts.]