Intelligence and Miscellanies. 193 
External shape spheroidal, or sub-angular. 
Structure lamellar, cleaving in two directions; at right an- 
les to each other, or as nearly so, as the perfection of the 
planes will allow us to observe. One of these cleavages is 
effected with greater ease than the other, and presents im- 
perfect horizontal. striz. The lamellar structure is often in- 
terrupted by a sub-conchoidal fracture. 
Lustre vitreous, and splendent in the most perfectly cleav- 
able masses, but glimmering only, on the conchoidal surfaces. 
Color grey, often with a tinge of blue, and rarely, olive green. 
Translucent onthe edges, andin a few instances, transparent. 
Hardness equal to that of crystallized adularia: the one 
impressing the other, only when great mechanical violence 
is exerted. It scratches the crystallized pyroxene of Mussa. 
i hich 
o pieces, weighed 6:1 grs.; the entire 
mass gave 3°3. and the largest fragment 3°38. Anothermass 
weighing 3°4 grs. gave a specific gravity of 3°90. The mean 
of the three experiments is 3°259 
Chemical Examination. 
Before the blow pipe, in small fragments, with the most 
intense heat that could be urged, it fused with ebullition up- 
on its thinnest edges into a shining black glass, and the frag- 
ment became immediately attractable by the magnet. With 
the ead commenced. The ratus was disengaged as 
soon as it was perceived by the smell (through the means of 
Vou. XVI.—N 25 
