ORDER vii. DODECAHEDRAL CORUNDUM. 295 



longing to the species of prismatic Disthene-spar. It has 

 often been erroneously considered as grey Andalusite. 



2. According to BUCHOLZ, the prismatic Andalusite con- 

 sists of 



Alumina 60-5. 



Silica 36-5. 



Oxide of Iron 4*0. 



Before the blowpipe it is infusible, even in thin splinters 

 or in powder, but it becomes covered with white spots. 

 It is difficultly soluble in borax, even when reduced to 

 powder, and almost only on the edges in salt of phos- 

 phorus. 



3. Crystals of prismatic Andalusite are found imbedded 

 in mica slate, or implanted in the cavities of rocks, forming 

 irregular beds or nodules in granite and primitive slate. 

 It is generally associated with rhombohedral Quartz, some- 

 times with Finite. 



4. This species was first discovered in the province of 

 Andalusia in Spain, from whence it has been called Anda- 

 lusite. Varieties of it have been afterwards found near 

 Braunsdorf in Saxony, at Herzogau in the Upper Pala- 

 tine, in several places in France, and at Kaplitz on the 

 frontiers of Austria and Bohemia. Crystals of very consi- 

 derable magnitude are found in the valley of Lisenz near 

 Inspruck in the Tyrol. 



GENUS II. CORUNDUM. 

 1. DODECAHEDBAL CORUNDUM. 



Octahedral Corundum, second and third subsp. JAM. 

 Syst. Vol. I. p. 41. 43. Dodecahedral Corundum. Man. 

 p. 182. Spinelle Ruby. Pleonaste. PHILL. p. 90. 92. 

 Spinel (with exception of Salamstein). Zeilanit. WEEN. 

 HofFm. H. B. I. S. 530. 535. Spinell. Pleonast. 

 HAUSM. II. S. 360. 363. Spinell. LEONH. S. 511. 

 Spinelle. Ple'onaste. HAUY. Traite', T. II. p. 496. 

 T. III. p. 17- Tabl. comp. p. 31. Alumine magnesiee 

 on Spinelle (with exception of Sp. zincifere). Traite, 

 2de Ed. T. II. p. 166. 



