302 Count de Bournon’s Description of 
shape ; sometimes, however, the appearance of a regular form 
may be observed in them. 
The fibrolite is in much greater proportion in this matrix, 
than in that of the imperfect corundum from the Carnatic ; and 
it is more generally dispersed throughout its substance; its 
fibres, however, are shorter, and form small detached diverging 
pencils, which unite together, crossing and penetrating each 
other in all directions, so as to present masses of a more con- 
siderable size. In this manner, it often entirely surrounds the 
crystals of corundum, and it is then impossible to disengage 
them from it. Its most usual colour is a whitish gray, but it is 
also frequently of a dull white. It is sometimes mixed, nearly 
in equal proportions, with felspar, and the attractable black 
oxide of iron ; and thus produces a stone which, if polished, 
would have a very beautiful appearance. The analysis which 
Mr. Chenevix has made of this substance, concurs with all 
its other characters to demonstrate, that it is decidedly of the 
same nature as the fibrolite of which I have already spoken, as 
being found in the matrix of imperfect corundum from the 
Carnatic. 
The very attractable black oxide of iron is, of the various 
substances found in the matrix of imperfect corundum from 
China, that which is most constantly, and most universally, 
mixed with it. In the smallest piece of this matrix that can be 
broken off, some particles of the oxide may generally be per- 
ceived; even the crystals of the corundum itself are hardly 
ever free from it, it being observable, not only upon their ex- 
terior surface, but also within their substance. This oxide of 
iron is usually disseminated, in this matrix, in small masses 
