Seybert’s Analysts of Pyroxene. 149 
two easy cleavages in opposite directions. When fractured, 
it frequently yields very regular rhomboidal. fragments. 
Scratches glass, and scintillates with steel. Its specific gravi- 
ty is 3.407. It isnot magnetic. Before the blowpipe, it 
readily fuses into a black vitreous globule. _ 
. ANALYSIS... —— 
A. 3 Grammes of Pyroxene, finely pulverised, after ex- 
posure toa 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 
of alemon yellow colour, was evaporated toa 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 100. 
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 1- 
quor was evaporated to dryness to expel the excess 5 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 weig'- 
€d 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; 1 was filtered, 
toseparate the fluid from the dark coloured precipitate 
which was formed ; it was supersatura 
and then treated with an excess of ammonia : a white pre- 
