THE DIAMOND AND OTHER PRECIOUS STONES. 335 



dnced into the nioutb, for toothacbe or sore-tliroat, to secure it by a 

 string, to prevent its being swallowed by tlie patient. 



The study of precious stones, which may seem frivolous when these 

 are considered only as objects of oriiauient, rises in importance when 

 looked upon in connection with commerce, optics, and mineralogy. The 

 classic Haiiy, creator of crystallographic mineralogy, has not disdained 

 to publish a book on precious stones, in which he leaves nothing to be 

 desired in the way of description. In his prefoce he acknowledges his 

 obligations to M. Achard, mineralogist and lapidary, of Paris; and I 

 ought to say as much for M. Achard, the son, without whose aid I should 

 not have felt able to compose this article. 



What is the diamond ? It is the most rare and the most priceless of 

 minerals. What is carbon ? It is one of the most common of known 

 substances, found in the earth in immense quantities and furnished by 

 all plants and trees in great abundance. The diamond is priceless, 

 since one of pure quality, of the weight of a twenty-five-franc piece — 

 that is, of 123 carats — will have a money value of at least four millions 

 of francs. Kow, the value of an, equal weight of carbon is scarcely any- 

 thing, and yet the two are identical ; the diamond is only carbon crys- 

 tallized. Every one knows that if a body is dissolved in a liquid — for 

 example, common salt, saltpeter, sugar, or alum, in w^ater — the deposit 

 left by evaporation of the liquid will present regular geometrical forms. 

 Salt assumes a form identical wdth that of x>laying-dice, to which the 

 Greeks gave the name of cubes ; saltpeter jiresents elongated bodies 

 with four flat sides and square ends ; sugar takes the form known as 

 rock-candy; and finally alum crystallizes into pointed pyramids. This 

 latter form is precisely the same as that under which nature presents 

 us with the crystals of carbon called diamonds. 



As soon as the character of the diamond was discovered, chemistry 

 aspired to emulate nature in producing the gem from carbon ; but up to 

 this time science has been bafiied in her attempts — nature has not been 

 induced to reveal the secret of her i)rocess. These geometrical products 

 of nature, when not worn by attrition, are as smooth and as i)olished as 

 the finest cut glass. Colored crystals are also produced by nature as 

 w^ell as white ones. The red ruby, the blue sapphire, the green emerald, 

 the yellow topaz, the violet amethyst, and the crimson garnet are all 

 the products of her unrivalled laboratory. 



Chemistry, it is true, furnishes us with hundreds of crystals of differ- 

 ent forms, according to the character of the substances of whi(5li they 

 are composed, and many of them are not found in mineralogy. Nature, 

 however, as if by w^ay of revenge, has produced in the course of ages, 

 and under the influence of actions scarcely as yet recognized, crystals 

 which art, directed by science, has not been able to imitate. Such is 

 emphatically the diamond, and many other minerals not embraced among 

 gems. To the study of these geometrical forms, whether the products 

 of nature or of art, the celebrated Haiiy, about the beginning of this 



