Quantcast
  We apologize for any slow response. This will be fixed before October 31st Portal logo
Login/Register
Bactrian Gold Treasure from Afghanistan, coming soon....
/gemstones/king-gems-decorative-stones/page_244 - 2
 

Onyx, Nicolo

Onyx, Nicolo Page of 384 Onyx, Nicolo Text size:minus plus Restore normal size   Mail page  Print this page
ONYX.
235
became brown and transparent after having been worn a few hours upon the finger, in consequence of the ab­sorption of the perspiration from the skin by its porous substance. Not being aware of the cause, he supposed the gem to be a Hydrophane or Oculus Mundi, a kind of Opal that goes through a similar change if saturated with water. Similarly another gem of mine, a fine Sard, engraved with a head of Sapor II., filled with white spots owing to a partial calcination, recovers its pristine pure and crimson transparency after a few days' wear on the finger. These experiments tend to verify Pliny's recipe for improving the lustre of the Carthaginian Carbunculus (above quoted), by a fortnight's maceration in vinegar.
Ben Mansur describes the Onyx (Dschesi) as divided into two species :—The Bahrawi of three layers : the first, opaque red ; the next white ; the third, transparent like crystal : and the Haheschi, also of three layers—two dark, and a white one between them (the actual ïíý÷ùí of the Greeks). " Some are striped, othors are not : in others the stripes are so interrupted that they form curious figures." * Interesting also is his notice of the localities yielding it :— " Although the Onyx is found in many places, yet those most valued are dug up on the confines of India and of China." From which it appears that, like the early Greeks, the Persian mineralogist makes no distinction between the Onyx and the Sardonyx.
In the same measure as the Alexandrian glass-workers counterfeited with astonishing success the natural clouds and polished surface of the Murrhina, so did they repro­duce with equal skill, in their cheaper material, the pre­cious Onyx vases and the cameo designs embellishing their surface. This was effected by fusing an opaque white
* On which account it faires with us the popular name of "Fortifica­tion-Agate."
Onyx, Nicolo Page of 384 Onyx, Nicolo
Suggested Illustrations
Other Chapters you may find useful
Other Books on this topic
bullet Tag
This Page