OBDEB V. PYRAMIDAL EUCHLOEE-MICA. 183 



are in a parallel position with P horizontally 

 streaked ; [P + oo] rough. 



Lustre pearly upon P oo, both as faces of crys- 

 tallisation and of cleavage ; adamantine upon 

 the other faces. Colour emerald-green, and 

 grass-green, less frequently leek-green, apple- 

 green, or siskin-green. Streak corresponding to 

 the colour, though paler. Transparent ... trans- 

 lucent, sometimes only on the edges. 



Sectile. Hardness = 2-0 ... 2-5. Sp. Gr. =3-115, 

 a variety from Gunnislake, Cornwall. 



Compound Varieties. Massive: composition gra- 

 nular, of various sizes, faces of composition rarely 

 observable. 



OBSEBVATIONS. 



1. According to Mr R. PHILLIPS (Ann. of PhiL New 

 Ser. V. 57-)? the present species consists of 



Oxide of Uranium 60-00. 



Phosphoric Acid 16-00. 



Oxide of Copper 9-00. 



Silica 0-50. 



Water 14-50. 



Alone it becomes yellow before the blowpipe, and loses 

 its transparency. Upon charcoal it intumesces a little, and 

 melts into a black globule, with traces of crystallisation 

 upon the surface. With borax it yields a yellowish-green 

 bead, and produces a yellow solution in nitric acid. 



2. The varieties of pyramidal Euchlore-mica occur upon 

 veins of copper, silver, tin and iron ores, and also some- 

 times in beds. It is accompanied by ores of copper, tin, and 

 uranium, generally by rhombohedral Quartz, less frequent- 

 ly by rhombohedral Emerald or prismatic Feld-spar. 



3. Beautiful varieties have been obtained from Gunnis. 



