Professor Gmelin's Analysis of Mica. 199 



Abt. II.— Analysis of a Peach-Blossom Coloured Mica, from 

 Chursdorf, near Penig, in Saxony. By C. G. Gmelin, 

 Professor of Chemistry in the University of Tubingen. 

 Communicated by the Author. 



The researches of M. L. Cordier * had made it extremely pro- 

 bable that Mica and Lepidolite are one and the same mi- 

 neralogical species. By the discovery of lithion in Lepi- 

 dolite, there was established a difference between these two 

 minerals, which, though it might not prove a specific diversi- 

 ty, according to the views of mineralogists, was still interesting 

 to the chemist, and explained the great difference in the de- 

 gree of fusibility of both minerals. But though Lepidolite 

 and Mica very nearly agree with each other, as well in their 

 physical relations as, on the whole, in their chemical composi- 

 tion, yet the argument for such an identity is strengthened 

 by the discovery of a real Mica with large laminae, fully agree- 

 ing in chemical composition with Lepidolite. 



Considering that Amblygonite, a mineral which, among 

 those hitherto known, contains the largest quantity of lithion, 

 occurs in a newer granite, together with a great many other 

 minerals, as Tourmaline, Mica, Topaz, Alhite, Apatite, &c. I 

 supposed that this alkali might not be found exclusively iivam- 

 blygonite, but might also occur in other fossils accompanying- 

 it, as it forms an ingredient of spodumene, lepidolite, tour- 

 maline, minerals that occur in the Island of Uton. I requested, 

 therefore, my friend, Mr Breithaupt, to provide me with spe- 

 cimens of fossils found in the neighbourhood of amblygonite. 

 Amongst these the peach-blossom coloured Mica first attracted 

 my attention, and reminded me of Lepidolite by its exceedingly 

 great fusibility. By the purple colour, which I afterwards per- 

 ceived in the flame of the blow-pipe in which this Mica was 

 melted, I became fully convinced of the presence of lithion in 

 this Mica, and of its identity with Lepidolite. 



A. Specific Gravity of this Mica, — Three very pure bits 

 weighed in the air 5.08 grammes. Having been previously 

 freed from adhering atmospheric air by means of a moistened 

 pencil, they weighed in water of + %° Reamur, 3.293 gr. 



• Gilbert's Annalen, vol. xi. p. 250. 



