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BOOK VII
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161
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tain
named for virgins, the other behind the shrine of St. Nicholas. It may
be gray, black, liver-colored, yellow, etc., but these are worthless.
This
rock varies in hardness. The Chemnitz material from the oblong mountain
is soft, as is the material from the red quarries of the Pallien-ians,
Fidenae and Albans. Some is moderately hard as that from the deep
quarry behind the shrine of St. Nicholas and the quarry in the woods to
the right. This rock was used to build the famous monastery of St.
Benedict on a small mountain outside the town. The Tiburtian,
Amiternian and Soractian quarries have produced this same type of rock.
That from the mountains near Mulde between Penica and Roseburg is hard.
The temple of Cosus under the sovereignty of Anhalt is made from blocks
of a very hard rock, in fact it is so hard it can only be dressed with
iron tools and even then only with the greatest of difficulty. This
genus, especially when it is soft or moderately hard, usually contains
impurities. Sometimes it contains marl that makes holes since the marl
falls out when the stone is dressed. Sometimes it contains flint,
especially black flint that tends to break from the rock when struck
with a hammer and thus make the surface uneven. Sometimes it contains
small pebbles similar to gems and although these appear, at first, to
enhance the beauty of the stone, during dressing these tend to drop out
leaving holes. These can be observed in Elboganun and especially in the
walled city of Herzberg.
The very white rock of Megara and other softer varieties contain marine shells throughout and for that reason are called lapis conchites.16 This
rock was used, according to Pausanias, in the monument of Phoroneus and
in many buildings in the city of Megara. The same genus is found in
Thessalia, Haemon, Macedonia, and the mountains of Calabria. Similar
rocks quarried near Paris often contain snail shells. Recently a rock
was quarried that carried an impression similar to a crown of laurel.
The
soft rocks can be dressed with ease with an iron tool but the hard
rocks can be dressed only with the greatest difficulty even after they
have been left exposed to the air for some time. The moderately hard
rocks are dressed with moderate ease. When the soft varieties are
exposed to the weather they crumble and dissolve in the rain while the
ice and frost break them into small pieces. Some cannot stand the heat
of the sun and near the ocean they crumble because of the salt air. In
protected places, however, they can sustain heavy loads. The
moderately hard rocks sustain heavy loads in exposed places and
withstand rain and cold but break up in a fire. The hard stones are not
even injured by fire. Copper workers use this genus to make the
appropriate molds for casting molten copper. Some varieties are soft
and easy to work and still withstand fire and these are the ones most
suited for molds. Some rocks, dark gray in color, are found in Hesse
and are worked into all types of molds for casting different metals.
The same species is found in Siphnos and in Italy near Como
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Coquina and coquina marble.
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