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Book VIII metals, precious such as gold, platinum, silver

Book VIII metals, precious such as gold, platinum, silver Page of 251 Book VIII metals, precious such as gold, platinum, silver Text size:minus plus Restore normal size   Mail page  Print this page
176
DE NATURA FOSSILIUM
vessel where it forms a substance they call mercury sublimate. This has corrosive properties equal to quicklime and will even destroy the latter. Enough concerning quicksilver.
The Greeks call copper {aes) χαλκοί. It is found as a native metal not only in its own veins but also in silver veins. The old writers and even Al-bertus did not know this although the latter writes that the best and purest is found at Goslar mixed with all kinds of stones such as marchasita, his name for pyrite. Actually if it is found mixed with all kinds of stones it is not pure, much less the purest. It is purified by smelting. I do not know if copper is found in masses that equal the size of masses of native silver but small masses occur in different forms, for example, stalactites, small branches, globular masses, etc. Very thin foils are found adhering to stones. Native copper often contains small amounts of silver.
Copper has a characteristic red color. The finest color is found in the metal that has been smelted from veins. However the color varies. Some is the characteristic color such as that smelted at Neusohl in the Carpa­thian mountains of Hungary; from Cotteberg, Bohemia; from Norway; and from the Harz forest. Some is a dark red as that from the Gairum and Schneeberg mines, Misena. Some from Gairum is whiter and we are wont to call it white copper even when it is also dark red. Pliny mentions white copper but does not say if it was smelted from a vein or tinted with lodestone. A yellowish red copper is produced in smelters that separate silver from copper and this is called yellow or regulare copper. In the same smelters a dark yellowish-red copper is produced which is known as caldar-ium copper. The German name for this13 is derived from lebes, a bronze cauldron. I shall say more about each of these later. Regulare differs from caldarium copper in that the former is easier to forge than cast, the latter easier to cast than forge, in fact it breaks under the hammer. Copper con­taining zinc has a golden color and is called opeixakKos. Pliny writes that this is also found in mines and for a long time was regarded as especially beautiful and desirable. Lodestone gives it a white color. Chemists can change the color to silver or gold so that it resembles varieties of these metals. It glows in a fire, melts and can be cast. Copper is not affected by fire when placed in a large shallow vessel, yet when placed in the same ves­sel with the materials that purify gold and silver it is entirely consumed. It is hard but can be hammered into thin sheets. Pliny writes that when copper is beaten into sheets and tinted with the gall of a bull it resembles gold and since it is used in crowns that are worn by actors it is called coronarium copper. When one-sixth ounce of gold is added to an ounce of this copper a thin sheet burns with a flame the clear red color of pyrope garnet. Copper objects such as nails are shattered by the force of cold. Eratosthenes tells of a copper jug which a priest named Stratius placed in the temple of Aesculapius near Panticapaeum and was broken by the
13 Lebetezkupfer.
Book VIII metals, precious such as gold, platinum, silver Page of 251 Book VIII metals, precious such as gold, platinum, silver
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