POPULAR SEARCHES:   cut stones  rings  diamond ring  necklaces  tanzanite  tourmaline  
 
This chapter is tagged (labeled) with: 

Sec. II, Ch. 1: The Diamond

Sec. II, Ch. 1: The Diamond Page of 366 Sec. II, Ch. 1: The Diamond Text size:minus plus Restore normal size   Mail page  Print this page
68
The Diamond.
Diamond, heated in an atmosphere of carbonic acid, by means of the oxy-hydrogen blow-pipe, gradually dis­appeared without any sign of softening. Morren has studied the behaviour of the Diamond when exposed to high temperature in various gaseous media.
Gassiot experimented on the Diamond by strong galvanic currents between carbon points, demonstrating that in burning Diamonds, uncrystallized black carbon is first produced, which at a very high temperature, burns off into carbon di-oxide ; that many rough Diamonds possessing a metallic lustre become leaden-grey, and that the blackish spots, adhering to the surface of some, may be got rid of by great heat.
Some very notable experiments on the action of heat upon Diamonds, were made some years ago, by the late Professor Gustav Rose, of Berlin. Enclosing the stones in strong glass vessels, from which the air had been ex­hausted, he subjected them to the intense heat of the electric arc produced by Siemens's powerful machines. Air being thus excluded, the Diamonds could not be consumed, but it was remarkable that they gradually became encrusted with a dark coating of graphitic carbon, resembling blacklead.
That the Diamond could be converted into Graphite when heated in the electric arc was clearly demonstrated as far back as 1847 by Jacquelain ; but quite recently M. Moissan, by means of his electric furnace, has carefully studied the phenomenon, and has found that the resulting Graphite occurs in irregular crystalline forms. At a very exalted temperature he has been able to volatilize carbon.
Professor Dewar, in his remarkable researches on liquid oxygen at the Royal Institution, has shewn that if a Diamond be strongly heated, and then suddenly thrown
Sec. II, Ch. 1: The Diamond Page of 366 Sec. II, Ch. 1: The Diamond
Table Of Contents bullet Annotate/ Highlight
Streeter: Precious Stones and Gems
Suggested Illustrations
Other Chapters you may find useful
Other Books on this topic
bullet Tag
This Page