446 CONSTITUTION AND VOLUME OF MINERAL SPECIES. [XVII. 



I have insisted upon the relation of isomerism, or rather of poly- 

 merism, which exists between meionite and zoisite, and have 

 remarked that the augmentation of hardness, of density, and 

 of chemical indifference which is seen in this last species, is 

 doubtless to he ascribed to a more elevated equivalent, or, in 

 other words, to a more condensed molecule. These different 

 degrees of condensation, which are constantly kept in view in the 

 study of organic chemistry, are besides, as I have already else- 

 where shown, of great importance in mineralogy, and will form 

 the basis of a new system of classification, which will be at the 

 same time chemical and natural-historical. (Comptes Rendus, 

 1855, Vol XLI. page 79.) The different rhombohedral carbon- 

 spars, kyanite and sillimanite, hornblende and pyroxene, offer 

 in like manner examples of different degrees of condensation, 

 and by their chemical composition belong to series the terms 

 of which, like those of the hydrocarbons nC 2 H 2 , are both 

 homologues and multiples of the first term. At the same time 

 each one of these carbonates and silicates belongs to another 

 possible series, the terms of which differ by nM 2 2 , corre- 

 sponding to more or less basic salts." 



"Meionite, with the oxygen ratios 3: 2: 1, is the most 

 basic term known of the series of the wernerites (scapolites). 

 The proportion of silica in these minerals augments until we 

 reach in dipyre the ratios 6:2:1, with a density which does 

 not exceed 2.66. We might then expect to find a silicate 

 which should be to dipyre what zoisite or saussurite is to 

 meionite, and Mr. Damour has recently had the good fortune 

 to meet with such a mineral in a specimen of jade from China, 

 of which he has given us the description and the analysis. 

 (Comptes Rendus, May 4, 1863.) This substance closely 

 resembles in its physical and chemical characters the saussurite 

 or jade from Monte Rosa, of which it has the density, 3.34. 

 It is a silicate of alumina, lime, and soda, and gives the same 

 empirical formula as dipyre. We may expect to find between 

 saussurito and this new species, to which Damour gives the 

 name of jadeite, other jades having formulas which will corre-' 

 spond with the wernerites intermediate between meionite and 



