ORDER XII. DODECAHEDRAL GARNET-BLENDE. 33 



3. D. - Fig. 162. Alston Moor* Cum. 



berland. 







4. -r-' D. < Kapnik, Transylvania. 



5. H. 5- D. ^- Alston Moor. 



Cleavage, dodecahedron highly perfect. Fracture 

 conchbidal. Surface, the tetrahedrons and the 

 two tetragonal dodecahedrons generally, though 

 faintly streaked parallel to their common inter- 

 sections ; the trigonal dodecahedron is often un- 

 even or curved, but at the same time smooth and 

 shining. 



Lustre adamantine. Colour green, yellow, red, 

 brown, black, none of them bright. Streak 

 white . . . reddish-brown 5 corresponding to the co- 

 lour. Transparent ... translucent. 



Brittle. Hardness = 3-5 ... 4-0. Sp. Gr. = 4-078, 

 a cleavable variety ; 4*027, a columnar, com- 

 pound variety. 



Compound Varieties. Twin-crystals : face of 

 composition parallel, axis of revolution perpendicu- 

 lar to a face of the octahedron. Fig. 156. and 163. 

 This composition is often repeated, either in parallel 

 layers, or in the direction of several faces of the oc- 

 tahedron. Reniform and other imitative shapes : 

 surface rough ; composition columnar, often almost 

 impalpable ; straight, divergent, and frequently pro- 

 ducing a second curved lamellar, or granular com- 

 position. Massive : composition columnar or granu- 



f OL. in. e 



