1878. ] Diamonds. 429 
nent chemists of the present century have expressed the opinion 
that diamonds owe their genesis not to the action of heat, but to 
an organic process. Newton, when studying the optical quali- 
ties of diamond, came to the conclusion that it must be a 
“coagulated oil.’ By means of electricity very minute crystals 
of carbon have been obtained, but all efforts to reach greater 
size have been baffled. Liebig regarded the formation of dia- 
mond as the result of organic decomposition. Though this view 
may not be perfectly tenable, it commends itself to the poetical 
mind from its allusion to the rejuvenated phcenix rising from his 
own ashes. With an ever-increasing knowledge of chemistry 
and the constant improvement of mechanical appliances, we may 
yet, some day, be able to produce diamonds that will compare 
favorably with those fashioned by the skillful hand of nature. 
Practical uses of Diamonds—Dependent upon its physical 
properties, the diamond is put to various uses. Perhaps the most 
prominent is that of drilling. The comparitive cheapness of “ car- 
bon” makes it possible to utilize this material for such purposes. 
Diamonds with sharp, crystallized edges are used for cutting glass 
and small fragments, and splinters are used to arm graver’s tools. 
Dust is employed in cutting other stones as well as the diamond 
itself. Wherever a substance of very great hardness is required, 
diamond answers best. On account of its high power of refrac- 
tion, diamond-lenses were formerly prepared, for the use of very- 
high power instruments. The application of diamonds for purposes 
of personal or artistic ornamentation, may perhaps be considered 
a practical one in a certain sense. For such use the total absence 
of color and the high degrees of refraction and dispersion of light, 
place the diamond in the most prominent position among all 
precious stones. : 
Imitations —1It is natural that a stone so valuable as the diamond 
should frequently be imitated. Pastes are manufactured to-day, 
which only a very experienced eye can detect as frauds Admix- 
tures of lead and, recently, thallium, impart to paste a high angle 
of refraction, thus producing “flashing” effect very near that of 
the diamond. Colorless quartz crystals and topaz are frequently — 
cut and are destined to simulate diamonds. Zircon, if heated for 
a short time, turns colorless from a bright blood-red, and is cut. 
This too, in smaller settings supplies the place of the diamond. 
Quartz and Zircon-can readily be detected by the difference of — of 
Specific gravity. The former is 2.65, the latter 4.30, while poe 
