348 PHYSIOGRAPHY. CLASS II. 



of Magnesia. PHILL. p. 181. Borazit. WERN. Hoffm. 

 H. B. III. 1. S. 138. Borazit. HAUSM. III. S. 821. 

 Borazit. LEONH. S. 509. Magne'sie boratee. HAUY. 

 Traite, T. II. p. 337. Tabl. comp. p. 16. Traite', 

 2de Ed. T. II. p. 56. 



Fundamental form. Hexahedron. Vol. I. Fig. 1. 

 Simple forms. H (P) Segeberg, Holstein ; (s) 



Vol. I. Fig. 13. ; -2 (s') Vol. I. Fig. 14; D 

 (ri) Vol. I. Fig. 31.; -' (r) Vol. I. Fig. 16.; 



*|i (x) Vol. I. Fig. 35. 



Char, of Comb. Semi-tessular with inclined faces. 

 Combinations. 1. ~. D. 2. H. y. D. Fig. 159 and 



160. 3. H. y. D. ^-. 4. H. ^. . 



C* T< 



D. . . AH of them from Liineburg. 



Cleavage, traces parallel to the faces of the octa- 

 hedron. Fracture conchoidal, uneven. Surface, 

 smooth and shining, only the inverse halves 



and ~ are sometimes rather rough and 



uneven. 

 Lustre vitreous, inclining to adamantine. Colour 



white, inclining to grey, yellow, and green. 



Streak white. Semi-transparent, translucent. 

 Hardness = 7-0. Sp. Gr. = 2-974 of an isolated 



crystal. 



OBSERVATIONS. 



1. This substance has been hitherto found always 

 in crystals, remarkably well pronounced. According 



