THE DIAMOND AND OTHER PRECIOUS STONES. 361 



one of these shells in finely prepared wax, we get the colors as well as 

 the form of the specimen. Myrrhine vases were sold at 70, 100, and 300 

 talents. The talent was about 540 francs. We may find among miner- 

 als mauj" stones which, being- cut, will make excellent gems. There is 

 the euclase, a weak emerald in color, but not so hard as a real emerald. 

 The ampMgene is as pretty as the white sapphire. The i^rehnite is a. 

 tolerably good celadon. It is somewhat remarkable that researches in 

 mineralogy have led to nothing new in the way of precious stones. This 

 illustrates a remark of Humboldt that mineral nature is the same from 

 one end of the world to the other, which cannot be said of either the 

 vegetable or the animal kingdom. 



There is no hope, then, of our finding anything beyond diamonds, ru- 

 bies, sapphires, topazes, emeralds, and amethysts. The only resource 

 is the laboratory. To obtain new gems man must not count upon nature 

 but upon his genius. 



In terminating the list of precious stones let us say a word about the 

 white pebble or rock-crystal. This is nothing but flinty sand, crystallized 

 and variously colored. Almost all false gems, so called, are made from 

 rock-crystal or quartz. Thus rock-crystals, cut like the diamond, as 

 Ehine diamonds and Alencou diamonds, are called false diamonds. It is 

 only violet quartz which makes the true amethyst. Recentlj' an attempt 

 has been made, with considerable success, to imitate the yellow topaz 

 with rock-crystal of the same color. There is develoi)ed in the stone a 

 very rich, velvety, orange color. As to all the reflections, the tints, the 

 degrees of transparence, or of opalescence — in fine, of all the forms which 

 quartz, a veritable proteus, can assume, a volume would hardly suffice 

 to detail them. Formerly rock-crystal was used for chandeliers and 

 many other articles for which glass is now substituted. The ancients 

 were cognizant of the power balls of rock-crystal possess to concentrate 

 the sun's rays and of setting fire to bodies. Physicians also used them 

 to cauterize certain wounds, in accord with the adage, "After medi- 

 cine, the knife; after the knife, fire; after fire, nothing." These balls can 

 likewise be employed as microscopes, especially when they are small. 

 Minute nature might have been studied as well by the ancients as in our 

 day had they beeu so inclined. 



I have not mentioned turquoises, of which there are two kinds, 

 both without transparency, One of these is made from the teeth of 

 the mastodon and colored with copper, a grecii celadon. It is a kind 

 of fossil ivory. The other is a true mineral of the same greenish 

 blue color, and is a great deal admired ; it costs about forty francs 

 the caret. The turquoise is perfectly imitated by porcelain. This 

 stone, without transparency, can scarcely be reckoned among gems : 

 it is rather a kind of natural enamel. We have also omitted feldspar, 

 which contains an alkaline principle, and which yields stones having a 

 mother-of-pearl luster, but without colors. However, when feldspar is 



