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Book VI gems: diamond, emeralds, sapphire, topaz, chrysoberyl, carbuncle, jaspis

Book VI gems: diamond, emeralds, sapphire, topaz, chrysoberyl, carbuncle, jaspis Page of 251 Book VI gems: diamond, emeralds, sapphire, topaz, chrysoberyl, carbuncle, jaspis Text size:minus plus Restore normal size   Mail page  Print this page
120
DE NATURA FOSSILIUM
the two in Nero's possession, but even wine ladles such as the one Pliny mentions which was purchased for eight hundred and fifty pieces of gold
from a none too wealthy woman Η---------s, as well as the faceted spheres
with which we calculate prices. It is also cut into the faceted hemispheres from which they make the clusters that are set in rings. Quartz can be used for relief engraving, especially for coats of arms although it is rarely employed for this purpose since it wears rapidly \vith use being softer than a file. It is also used for the lenses that were employed by physicians in times gone by to burn people when held in the sun's rays. These lenses produce a dazzling white point of light that can shatter quartz itself and set fire to material. Hephaestites is also used for these lenses. Quartz itself is cold and dry. When an object is placed before it, it will illuminate the portion nearest it with its brilliancy. The more transparent and brilliant the quartz the greater its heating power.
Quartz is used in medicine. Having been ground very fine and taken in sour wine it stops dysentery since it is so drying.
The finest quartz is free from all flaws, transparent and heavy. This variety is found in the Alps near Sion and the finest crystals of Germany come from Gombezanus. All other quartz is of inferior quality. Actually writers judge the beauty of quartz according to its place of origin. Pliny writes that the finest comes from India and praises the groups of crystals found in the Alps. He writes that the very poorest comes from Asia near Alabanda and Orthosia. Solinus writes that the Scythian crystals are the most valuable. When the rays of the sun coming through an open door, window or crack are allowed to fall on a crystal of Scythian quartz it will reflect the rays on a nearby wall with all the colors of the rainbow and for that reason it is called iris. This can only be done with colorless, transparent, natural hexagonal crystals. Indeed it is because of its angles that it can take the rays of the sun and reflect them on a wall as a rain­bow. The crystal that will produce the largest rainbow with the brightest colors is regarded as the best. If any one of the angles of the crystal is turned toward the light and observed carefully a rainbow can be seen within the crystal. Iris is found in the localities mentioned above along with other quartz but it is especially abundant along the Weser river near the town of Hoxer; in Westphalia near Erz on the estate called Hil-deschespred; in Hesse near Halleberg; and in the mountains between Trier and the Rhine. Pliny writes that it is dug up on an island in the Red Sea forty miles from the town of Berenice.
There is another variety of iris that is not as colorless as quartz and when turned toward the light has a color as yellow as citron. For this reason gem dealers call it citrina.s Older writers have described this variety as resembling wax. Since it is not as transparent as quartz it is not as brilliant and the colors of the rainbow it throws on the wall of a room are
8 This is the first use of the name citrine for yellow quartz. The name citrina should not be confused with citrinus a variety of chrysolithos.
Book VI gems: diamond, emeralds, sapphire, topaz, chrysoberyl, carbuncle, jaspis Page of 251 Book VI gems: diamond, emeralds, sapphire, topaz, chrysoberyl, carbuncle, jaspis
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