Seyberfs Analysis of various Mineralso 117 



On comparing the oxygen of the Silica, with that of the 

 bases, it is evident, that it forms with them Bisihcates, and 

 the mineralogical formula is MgS^ -\-2CaS^ -{-2FeS^ . 



3. Colophonite, 



Occurs frequently disseminated and imbedded with 

 green Pyroxene in Tabular spar, sometimes it forms con- 

 siderable veins in that mineral. Colour in mass, deep red- 

 dish brown, in the state of powder it has a yellowish tinge. 

 Irised on the outer surface. Lustre resinous. Granular, 

 the single grains are highly translucent Fracture of the 

 mass irregular, the grains have a cleavage. Scratches glass 

 and scintillates with steel. Easily frangible. Not magnet- 

 ic. Specific gravity, 3.896. Fusible before the blowpipe 

 into an opaque black bead. 



*^nalysis. 



A. 3 grammes of the pulverized mineral after exposureto 

 a red heat weighed 2.99 £;rammes therefore the moisture dis- 

 sipated by this treatment amounts to 0.01 grammes, on 3 

 grammes or0..;33 per 100. The protoxide of Iron absorb- 

 ed no oxygen for the color was not altered. 



B. The calcined mineral, (A) when boiled with nitro- 

 muriatic acid became gelatinous, yielding a solution of a 

 reddish yellow colour, the v. hole was evaporated to a dry 

 mass, it was then heated with water, acidulated with muriat- 

 ic acid, and again moderately evaporated ; the residue was 

 treated with water and filtered, the Silica remaining, on the 

 filter after being washed and heated to redness weighed 1.14 

 grammes on 3 grammes or 38.00 per 100, This product 

 on examination proved to be free from Titanium. 



C The filtered liquor (B) was neutralized with caustic 

 potash, the solution when heated with the hydro sulphate of 

 potash gave a black precipitate which having been heated 

 as in the analysis of the Tabular spar yielded a residue 

 weighing 1,00 grammes, this was repeatedly calcined with 

 3 times its weight of caustic potash, no camelion having been 

 produced, it was evident that the mineral in question con- 

 tained no manganese. After the entire separation of the 

 Alumina was effected the Peroxidei of Iron weighed 0.82 



