92 PHYSIOGRAPHY. 



Bucbolzite. 



BUCHOLZITE. P r i s m a t o i d a 1 A x i n i t e. 



Primary form. Oblique rhombic prism. M on M' 99 

 30' ? Only the primary crystal with curved faces has been 

 observed ; and this without regular terminations. 



Cleavage parallel with the longer diagonal perfect ; par- 

 allel with P and M, visible, but indistinct. Fracture con- 

 choidal to uneven. 



Lustre vitreous. Color shades of greyish white and 

 hair-brown; sometimes presenting a metalloidal appearance 

 upon M. Bluish opalescence rarely observed upon cleav- 

 age faces parallel to M. Streak white. Translucent. 



Brittle. Hardness = 7-5 . . . 8-0. Sp. gr. = 3-2. 



Compound Varieties. Massive : composition columnar, 

 consisting of delicate, straight or slightly curvilinear indi- 

 viduals, strongly coherent, and sometimes nearly impalpa- 

 ble. Viewed in the longitudinal fracture the lustre is silky ; 

 but in the cross fracture, which is even and splintery, it is 

 resinous. 



1. The identity of Sillimanite with the present species appears proba- 

 ble, not only from the resemblance in the properties of hardness and 

 specific gravity, but in that of crystalline structure ; the perfect crystals 

 of the former often becoming compound and fibrous at one end; and the 

 less impalpable masses of Bucbolzite, exhibiting crystals which afford 

 the brilliant cleavage surfaces parallel with the longer diagonal of Silli- 

 manite. The disagreement in chemical composition, it is presumed will 

 disappear on searching for zirconia in future analyses of Bucholzite. 

 Before the blow-pipe, alone, and with borax, infusible. 



2. Analysis. 



ByBowEN, ByMuiR, ByBRANDEs, By HILTON & 

 from from from MITCHELL, 



Chester, Ct. Chester, Ct. Tyrol, fr. Chester, Pen. 



Silica . 42-666 38-670 46-00 46-40 



Alumina . 54-111 

 Zirconia . 0-000 



Oxide of iron 1999 

 Water . 510 



Potash . 0-000 



35-106 



18-510 



7-216 



0-000 



0-000 



50-00 

 000 

 2-50 

 0-00 

 150 



52-92 



0-00 

 a trace. 



0-00 



0-00 



