IKON ORMS. 229 



to the base, almost like mica ; laminae brittle and not flex- 

 ible. 



Color bright clear yellow and green ; streak a little paler. 

 Luster of laminae pearly. Transparent to subtranslucent. 

 H=2— 2-5. Gr=3— 3-6. 



Composition. .Tire re are two ores here included, the yel- 

 low one containing phosphoric acid 16, oxyd of uranium 63, 

 and lime 6, with water 15 ; the other of a green color, 

 (sometimes called chalcolite,) containing oxyd of copper in 

 place of lime. They fuse before the blowpipe to a blackish 

 mass, and the green variety colors the flame green. 



Dif. The micaceous structure connected with the light 

 color is a striking character. The folia of mica are not 

 brittle like those of uranite. 



Obs. Occurs with uranium, silver and tin ores. It is 

 found at St. Symphorien, near Autun, and also near Limoges, 

 and in the Saxon and Bohemian mines. Cornwall affords 

 splendid crystallizations of the green variety. 



Found sparingly at Middletown, Conn., and Chesterfield, 

 Mass., of a yellow color. ~*4^^*~(^ 



Samarskite (formerly named uranotantalite and yttro-ilmenite) is a 

 compound of oxyd of uranium with columbic and tungstic acids, from 

 Minsk in the Ural. It is of a dark brown color and submetaliic luster. 

 H=5o. Gr=5 - 4 — 57. Also occurs in North Carolina. 



Johannite or uranvitriol is a sulphate of uranium. It has a fine 

 emerald-green color, and a bitter taste. From Bohemia. 



14. IRON. 



Iron occurs native or alloyed with nickel in meteoric iron. 

 Its most abundant ores are the oxyds and sulphurets. It is 

 also found combined with other metals, and with silica and 

 carbonic and other acids. Its ores are widely disseminated. 

 They are the ordinary coloring ingredients of soils and many 

 rocks, tinging them red, yellow, dull green, brown and black. 



The ores have a specific gravity below 8, and the ordi- 

 nary workable ores seldom exceed 5. Many of them are in- 

 fusible before the blowpipe, and a great part become attract- 

 able by the magnet after heating, when not so before. When 

 undisguised by other metals, they afford with borax, in the 



What is the color and structure of uranite 1 its composition 1 How 

 is it distinguished from other species? What is said of the modes of 

 occurence of iron ? What characters of its ores are mentioned ? 



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