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Book VII marbles, gems in rings and other applications

Book VII marbles, gems in rings and other applications Page of 251 Book VII marbles, gems in rings and other applications Text size:minus plus Restore normal size   Mail page  Print this page
158
DE NATURA FOSSILIUM
soft as that from Zuicca, Misena, some medium hard as that from Pirna, while some is hard as that from Norinberg across the Danube. The latter material is soft when it is first broken in the quarry and therefore is worked at once since it becomes quite hard after standing in the air for some time. The rock from Zuicca will not withstand rain or cold weather. Cliffs of this rock in France between Colebach and Cuperberg, when exposed to the air, gradually disintegrate to sand. One variety from Pirna is composed of a very fine sand and has a smooth surface when sculptured. The rock from Rochlitz is so coarse that it cannot be given a smooth surface. Some rock is similar in appearance to fish roe such as that found between Eisleben and Seberg and within the sovereignty of Bruno at Noteberg. This re­sembles salmon roe which is about the size of rape seed. Another variety found between Eisleben and Seberg is composed of sand the size of cori­ander seed, blackish red in color and covered with a sweetish efflorescence.
Rock usually occurs in large masses and in quarries large angular blocks can be obtained. More rarely it occurs in thinner beds as near Bodeberder and Embach, Saxony. Rock from these thin beds is spread on roads in many places and is used in both private and public buildings. At both Embach and Bodeberder they spread it on the roofs of houses. The rec­tangular masses are used to build shrines and temples and especially for columns, windows and door posts. Material which will harden in air is preferred, for example that from Norinberg mentioned above. The well known wall of the fortified city of Dresden is built of this stone and the road to the famous bridge of the Elbe passes through an arch of this wall. A portion of the fortress of Berlin is built of the same rock. It is carried to distant and foreign countries via the Elbe river.
They make millstones from harder and denser rocks and for that reason the Greeks call them μυλίας or μυλίτψ, and the Latins, following the Greeks call them lapis molaris. Such rocks are found in Saxony near the town of Munda; in Misena near the fortress of Loma some three miles from Pirna. The millstones are transported from the former locality via the Weser river and from the latter via the Elbe. Another type of mill­stone is found in places that are burning. This rock forms from molten stone and was called lutum by Strabo and since it contains an admixed portion of a burning substance it has a moderate unctuousness. When these burning places erupt they throw out this molten stone and rivers of it flow away as can be seen at Etna. This soon congeals in the cold air and is changed into rock which can be quarried just as any other rock, although Pliny writes that this is a stone, not a rock. It is only found in those places that were burning at one time or are burning today. Even when the molten material is not thrown out it is congealed by the cold of the earth and changed into rock. Such a material is quarried in Italy near Lake Vulsiniis and in the district of Statonius; on the island of Nisida; and on Cape Melaena, Ionia. We do not know if the rock found in Mesopotamia near the Euphrates belonged to this genus or some other.
Book VII marbles, gems in rings and other applications Page of 251 Book VII marbles, gems in rings and other applications
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