ZEAGOXITE. . 175 



Cleavage imperfect parallel to P + oo. Surface, P 

 frequently rounded, P -f GO smooth, and though 

 generally very small, yet possessing high degrees 

 of lustre. Fracture conchoidal. 



Lustre adamantine. Colour pale smalt-blue, milk- 

 white, pearl-grey, and rose-red. Translucent, in 

 small crystals nearly transparent. 



Hardness = 7*0 ... 7-5. 



According to CARPI, it consists of 



Silica 41-4. 



Lime 48-6. 



Alumina 2-5. 



Magnesia 1 '5* 



Oxide of Iron 2-5. 



It phosphoresces before the blowpipe, and becomes friable, 

 but is infusible. It gelatinises with acids, without effer- 

 vescence. It occurs along with white octahedrons of oc- 

 tahedral Fluor-haloide, with prismatic Feld-spar and other 

 species in the drusy cavities of a volcanic rock at Capo di 

 Bove near Rome. In all its characters, Zeagonite is most 

 nearly allied to pyramidal Zircon, as a variety of which it 

 has often been considered, the difference of the angles given 

 by Mr BROOKE being only 25' on the terminal edges, and 

 42' on the lateral edges of the fundamental pyramid. 

 Also the refraction is very considerable, and approaches 

 near that of the same species. Pyramidal Zircon will 

 therefore make an interesting point of comparison with 

 the Zeagonite, in future examinations of this mineral. It 

 is evident that the mineral, of which Mr PHILLIPS has 

 given the angle at the base of the four-sided pyramid = 

 96 30', and which is said to yield to the nail, must be an- 

 other species than that described above, the angles of which 

 have been ascertained by Mr BROOKE. The name of 

 Abrazile is sometimes applied to a mineral, which seems to 

 be a variety of paratomous Kouphone-spar (Vol. ii. p. 229.). 



