324 DESCRIPTIVE MINERALOGY. 



Pyrenaite ,or Pyreneite. Black or greyish-black and opaque. It occurs in small dodeca- 

 hedral crystals, which externally have a metallic-like aspect. 



Aplome. Resembles garnet in aspect and external form, but differs in having its planes 

 striated parallel with their lesser diagonal; which, according to Haiiy, indicates the cube as 

 its primary. 



Grossiila?-, or Grossidaire. Of an olive green colour ; translucent or semitransparent, and 

 occurring in trapezoidal or leucite-formed crystals. 



Magncsian Garnet. Occurs massive, and in dodecahcdral crystals variously modified. It 

 is slightly translucent on the edges, and has a deep hyacinth or brownish red colour. It con- 

 tains a large proportion of the protoxide of manganese. 



Melanite. This includes the velvet-black, opaque specimens. It occurs in rhombic dode- 

 cahedrons, whose edges are often replaced. Before the blowpipe, it yields a brilliant black 

 globule. 



Coloplionite — Garnet Rcsinitc. This is composed of rounded grains of various sizes, which 

 maybe easily separated. It is of a brown, red or yellow colour, and has a high resinous or 

 resino-adamantine lustre. 



Allochroitc. It has a greyish, dingy yellow or reddish colour ; a glimmering lustre, and 

 feeble translucency. It is massive, and has an uneven fracture. 



Pyrope. This variety occurs in roundish or angular grains of a deep blood-red colour, and 

 perfect transparency. 



Topazolile — Yellow Garnet. This has a topaz-yellow colour: translucent or transparent. 

 Occurs crystallized. 



Essonite, or Cinnamon Stone. Occurs in granular distinct concretions, and massive. It is 

 of a hyacinth or orange-yellow colour ; transparent or translucent ; has a resino-vitreous 

 lustre, and a conchoidal fracture. Phillips describes this as a distinct species. 



Chemical Composition. This is of course somewhat different in the different varieties. 



Almandine from New-York — Silica 42.51, alumina 19.15, protoxide of iron 33.57, oxide 

 of manganese 5.49 {Wucht7neister). 



Precious Garnet — Silica 35.75, alumina 27.25, oxide of iron 36.00, oxide of manganese 

 0.25 {Klaproth). 



Pyrenaite— SiYica. i3. 00, alumina IG.OO, lime 20.00, oxide of iron 16.00, water 4.00 

 {Vauquelin). 



Aplome — Silica 35.64, lime 29.22, oxide of iron 30.00, oxide of manganese 3.01, potash 

 3.25 (W'achtmeistcr). 



Grossular—HiWc^ 40.55, alumina 20.10, lime 34.86, oxide of iron 5.00, oxide of man- 

 ganese 0.48 [Wdclitmeister). 



Manganesian Garnet — Silica 35.83, alumina 18.06, protoxide of iron 14.93, protoxide 

 of manganese 30.96 (Seyliert). 



Melanite — Silica 35.5, alumina 0.00, hmc 32.50, oxide of iron 25.25, oxide of manga- 

 nese 0.40 vl'f"'^!'?/"')' 



