MEMOIR ON EMERY. 



35 



MICA (MUSCOVITE?) 



This mica is found on all the emeries which I have exam- 

 ined, but especially on that coming from Kulah. It is always 

 in small plates on the surface of the emery. The analyses 

 of four specimens are as follows : 



Localities. 



to 



SO 



> 

 a 

 a 



5' 



go 





o 



P "> 

 '. O 



1.30 

 3.50 

 2.32 

 1.70 



SO 

 3 



p' 



£* ° 



° ^"^ 



notesti- 

 mated. 



7.83 



not esti- 

 mated. 



9.76 



jo 



ST 



: 5 s 



Gumuch-dagli . 



Kulah 



42.80 

 43.62 

 42.71 

 42.60 



40.61 

 38.10 

 37.52 

 37.45 



3.01 

 0.52 

 1.41 



0.68 



trace. 

 0.25 

 trace, 

 trace. 



5.62 

 5.51 

 5.95 



5.20 



trace. 



trace. 



Kulah 





Island of Nicaria.. 



trace. 



The composition is very nearly that of the muscovite or 

 Muscovy glass, and until further examination I shall retain it 

 under that species, as particular care should be exercised in 

 making new species among the micas. 



CHLORITOID (A NEW VARIETY OF THIS MINERAL). 



It is found with the emery of Giimuch-dagh in considerable 

 abundance. Its structure is lamellar, cleaving without much 

 difficulty, and the surfaces exposed are always very brilliant. 

 In thin fragments it transmits the light and appears of a dark- 

 green color. The powder is greenish-gray. Its hardness is 6 

 and specific gravity 3.52. Heated in the flame of the blowpipe, 

 it loses water and becomes brown from the absorption of oxygen, 

 but does not melt. When heated without being in contact with 

 the air it loses its brilliancy and acquires the aspect of scales 

 from the blacksmith's forge. 



This mineral is attacked by the strong acids, but is only 

 completely decomposed by sulphuric acid. Melted with four or 

 five times its weight of carbonate of soda, it is rendered easily 

 soluble in hydrochloric acid. Great precaution was taken to 

 see that nothing but perfectly pure chloritoid was submitted 

 to analysis, and the possession of well-crystallized specimens 

 enabled me to do this without much difficulty. 



• The method of analysis was to break the mineral in small 

 fragments, to place it in a small platinum crucible, which was 

 introduced into an earthen crucible and surrounded by pulver- 



