SINGULAR CRYSTALLIZATION OF THE DIAMOND. {J^ 



There were two substances, the borax and charcoal, the Platina fused 

 „,.,. ij-'^ T with charcoiil 



action of which it was necessary to discriminate. In con- j^yi,e^ 



sequence Mr. Descotils treated pure platina with charcoal in 



a cracible, and observed, that the charcoal was sufficient, to 



produce its fusion. 



A button thus obtained at Arcueil had increased in weight Carburet of 

 ... . Ill platiiia. 



a little more than 0'03, which were owing to the charcoal, 



that had combined with the metal. Its specific gravity was 

 18. This carburet was very hard, very brittle, shining, and 

 lamellated internally. 



Mr. Descotils observed, that borax without charcoal could Borax alt-na 

 not effect the liquefaction of platina; yet, by means of ^'^^""^ ^"** 

 charcoal, borax, or more probably the boracic acid, enters 

 into combination with platina. He will publish the expe- 

 riments, to which these observations shall give rise, and 

 which he intends to pursue. 



XI. 



On a singular Crystallization of the Diamond : by Mr, GuY- 



TON-MORVEAU*. 



JL HE natural history of minerals being only a collection Natural histo 

 of facts sufficiently established to be admitted without ry of minerals 

 question, it is particularly important to confirm the reality , J^ e.tioa » 

 of those that rarely meet our observation, in ordei* to remove 

 doubts, and cut short disputes, which tend but to retard the 

 progress of science. 



Five years ago I published in the Annales de Chimie> a Crystallization 

 letter on tli«i crystallization of lazulite, the lapis lazuli ©f of l*?'"^^-**"'^ 

 the shops. The piece from which the accurate description 

 was then made by Lermina, and which presents a perfect dode- 

 caedron with rhombic faces, has been recognued by all who 

 have seen it in my collection with the fine ultramarine, 

 which Messrs. Desormes and Clement obtained from the 

 mass in which this crystal was imbedded. Their opinioa 



* Read to the Institute, March the 27th, ISOQ. Ann. de Cbim. toI. 

 iXX, p. 60. 



