430 : Diamonds. [July, 3 
diamond is 3.52. Besides the specific gravity the hardness will | 
be decisive, both can be scratched by topaz. Topaz is more 
difficult to distinguish. Its specific gravity is 3.40 to 3.65, very 
near that of the diamond. In this instance, as well as in those 
of quartz and Zircon, an optical test is the most convenient. In 
1858, the Brazilian ambassador Lisboa, presented a “diamond ” at 
the court of Vienna. It had been admirably cut in Paris, and 
weighed 819 carats. By experts it was valued at more than fifty 
millions of francs. One of the mineralogists called in consulta- 
tion applied a very simple optical test, and found the stone to bea 
topaz. He placed a lighted candle upon a table, walked about 12 
to 15 feet away from it, and looked at the light through the 
diamond, which he held close to his eye. In every facet two 
little flames appeared side by side. As only those crystals have 
single refraction, which belong to the isometric system (in which 
_ the diamond crystallizes) the specimen under question, having 
double refraction, could not possibly have been a diamond. When 
looking in this manner at a candle, the diamond, as well as the 
paste will show but a single flame in each cut face. Paste can 
readily be distinguished by its inferior hardness, as opar will 
scratch it. 
Price —The price of diamonds is one that fluctuates, jeeni 
upon the demand and supply. Within certain limits it may be 
regarded as definite, but when the value of very large stones is to 
be estimated, the same rules for its determination cannot be fol- 
lowed. Diamonds are usually separated into three classes, and 
they are termed as being “first water,” &c. Besides these three, 
there is the boart and carbon. These two latter varieties are 
utilized for purposes of cutting, sawing, drilling, &c. They are 
sold by the carat as other diamonds. One carat of carbon costs 
-about 6 dollars. 
Diamonds used for purposes of ornamentation advance very 
rapidly in price as their size increases. If, for instance, one carat 
should cost 100 dollars, six carats will not cost 6 x 100 dollars, 
but 6 x 6 x 100 or 3600 dollars. This rule does not apply to 
inferior stones, but is followed, within certain limits, in determin- 
ing the value of the best class of diamonds. 
Independent of its high price, however, which is always a 
= recommendation to the favor of civilized man, and woman too, 
-~ the diamond will ever hold its own prominent position, on account 
7 its (em intrinsic value. . 
