Seybert^s Analysis of Pyroxene. 147 



two easy cleavages in opposite directions. Wiien fractured, 

 it frequently yields very regular rhomboidal fragments. 

 Scratches glass, and scintillates with steel. Its specific gravi- 

 ty is 3.407. It is not magnetic. Befors the blowpipe, it 

 readily fuses into a black vitreous globule. 



ANALYSIS. 



A. 3 Grammes of Pyroxene, finely pulverised, after ex- 

 posure to a red heat, became a shade darker, and weighed 

 2.965 grammes; therefore the dimunition by calcination was 

 1.166 per 100. 



B. The product of the calcination 'A,) was mixed with 

 9 gr. of caustic potash, and exposed to a red heat, during 

 thirty minutes, in a silver crucible. The matter did not en- 

 ter into perfect fusion, but assumed a pasty consistence; 

 when cold it was of a very deep green colour, which it im- 

 parted to ihe water used to dissolve it: an excess of muriatic 

 acid was added, when heat was applied a perfect solution 

 was formed with the evolution of chlorine. The solution, 

 of a lemon yellow colour, was evaporated to a dry gelati- 

 nous mass, which was treated with acidulated water and 

 again moderately evaporated ; more water was then added 

 and the liquor was filtered ; the Silica, remaining on the fil- 

 ter, after perfect edulcoration and calcination weighed 1.36 

 grammes on 3 gr. or 45.333 per lOO. 



C. Caustic potash was added to the liquor (B,) to neu- 

 tralise the excess of acid. On the addition of hydro-sul- 

 phate of Potash, a black precipitate was obtained, which 

 was well washed and treated with nitro-muriatic acid, the i- 

 quor was evaporated to dryness to expel the excess ; when 

 the residue was treated with water, it appeared that a por- 

 tion of the precipitate had resisted solution, the liquor there- 

 fore was filtered, the residue was moderately calcined, to 

 expel the sulphur, and after being heated to redness weigh- 

 ed 0.06 gr. This product was Alumina, and as it will ap- 

 pear, that no Alumina was taken up by the acid, the quantity 

 contained in the mineral amounts to 2.00 per 100. 



The filtered liquor was boiled, during thirty minutes, 

 with a considerable excess of caustic potash; it was filtered, 

 to separate the fluid from the dark coloured precipitate 

 which was formed ; it was supersaturated with muriatic acid 

 and then treated with an excess of ammonia : a white pre- 



