158 On the Identity of Sillimanite, Fibrolite, 
Select crystals of this mineral were taken from the original loca- 
lity at Chester, Conn, and their analyses afforded the following results. 
Quantity taken, 775°5 grammes. Found— 
Silica, é : , 0:292 = 37°653 per cent. 
Alumina, . - 4 0°484 = 62°411 
0-776 100:064 
Required. 
' 2 Atoms Silica, . . 115462 = Si O3 37°47 
3 Atoms Alumina, . 1927-00 = AP Os 62°53 
3081°62 100-00 
These results give, then, exactly the formula of Kyanite, viz., 
2 Al Os, 3 Si O*. The analyses of Staff and Norton give also the 
same results.* 
We can, therefore, have no longer any hesitation in referring Sil- 
limanite to Kyanite, as originally suggested by Haidinger. + 
Bucholzte, is a name given by Brandes to a silicate of alumina 
from Tyrol, which occurs in compact masses, of a finely fibrous struc- 
ture and hardness, equal to Kyanite. Thomson has also analysed 
a mineral from Chester County, Pennsylvania, well known to col- 
lectors, and has referred it to Bucholzite.t Being in possession of 
authentic specimens of the Chester mineral, I have analysed it with 
the following result. Quantity taken, 0°561 gr. Found— 
Another Sample. 
Silica, : : 01925 = 34:31 per cent. 35°96 
Alumina, - 0°3615 = 64°43. ... 
Magnesia, . 070028 = 0:52 
Manganese, : trace trace 
05568 99°26 
This, also, will give us the same formula as Kyanite. The mineral 
being less pure than Sillimanite, cannot be expected to furnish re- 
sults as accurate as the former analysis. Professor Shepard in his 
System, expresses the opinion, that Bucholzite and Sillimanite were 
the same species. 
* In Professor Norton's analysis, which was made in Yale College Labora- 
tory, the excess of 2°73 was owing, undoubtedly, to aluminate of potash, which 
remained with the alumina, after separating the peroxide of iron by caustic 
potash. Subtracting this sum from the sum of alumina and peroxide of iron, 
which is almost exactly the quantity required by theory, and I have corrected 
the analysis accordingly, with the consent of Professor Norton, That analysis 
was made on the Sillimanite from Fairfield, New York. 
t In his Translation of Mohs, vol. iii. 154. 
+ Erdmann appears also to have made his analysis on the mineral from 
the same locality. 
