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Seyhert'^s Analysis of various Minerals* 117 



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

 bases, it is evident, that it foj ms with ihera Bisilica'^^s, and 

 the mineralogical formula is ]V%S- +2CoS^4-2FcS^ 



3. Colophonite 



3 



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 slate 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. 



Analysis. 



■ r 



A- 3 grammes of the pulverized mineral after exposureto 

 a red heat weighed 2.99 grammes therefore the moisture dis- 

 sipated by this treatment amounts to 0.01 grammes, on 3 



grammes orO.:333 per 100. The protoxide of Iron absorb- 

 ed no oxygen for the color was not altered. ^ 



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

 muriatic acid became gelatinous, yielding a solution of a 

 reddish yellow colour, the whole was evaporated to a dry 

 inasSj it w^as then heated with water, acidulated with muriat- 

 ic acid, and again moderately evaporated ; the residue vvas 

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

 filter after being washed and h^ t^ted lo redness weighed 1-14 

 grammes on 3 grammes or 38 00 per 100. This product 



^ On examination proved to be (vQe 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 LOO 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 pffftp.ffid fhfi Pp.roxlde nf Iron weiffhed 0.82 



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