364 PHYSIOGRAPHY. CLASS n. 



ever, Pyrope is preferred to the rest, if pure and of consi- 

 derable magnitude. Common Garnet is useful as a flux of 

 iron-ores, and is in some countries called Green Iron-stone. 

 6. From the species of dodecahedral Garnet two sub- 

 stances are distinguished by HAUY, which may be here 

 shortly noticed. 



i. Aplome. 

 HAUY. Trait^, 2de Ed. T. II. p. 538. 



Form tessular. Combinations observed, 1. H. D. Fig. 

 151, the faces of the hexahedron small; 2. D. Ci.Fig. 154. 

 Cleavage, traces of the hexahedron. Fracture uneven. 

 Surface of the dodecahedrons streaked parallel to the edges 

 of combination with the hexahedron, which, however, is 

 not the case in the cleavable varieties. Lustre vitreous, 

 inclining to resinous ; high degrees upon faces of crystal- 

 lisation, low degrees in the fracture. Colour brown, some- 

 times yellowish. Streak white. Translucent on the edges 

 ... opake. Brittle. Hardness = 7-0 ... 7-5 (it scratches 

 rhombohedral Quartz). Sp. Gr. = 3-444, HAUY. It has 

 also been found massive. 

 According to LAUGIER, Aplome consists of 



Silica 40-0. 



Alumina 20'0. 



Lime 15-5. 



Oxide of Manganese 2-0. 



Ferriferous Silica 2'0. 



There was a loss of 7-0. Before the blowpipe it melts into 

 a black globule. The localities are, the banks of the river 

 Lena in Siberia, Schwarzenberg in Saxony and Bohemia. 

 Small brilliant, cleavable crystals are found in England. 



ii. Essonite. 



Dodecahedral Garnet, subsp. 8th. JAM. Syst. Vol. I. p. 

 162. Prismatic Garnet or Cinnamon-Stone. Man. p. 

 228. Cinnamon-Stone. PHILL. p. 32. Kaneelstein. 

 WEHN. Hoffm. H. B. I. S. 417- Idokras. HAUSM. 



