IRON. 171 



Joliannite or Uranmtriol is a sulphate of uranium, It has a fine 

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



Trogcrite and Walpargiie are uranium ars' nates. Voglite and 

 Liebigite are uranium carbonates. Jo/uinnite is a uranium vitriol ; 

 TIranochalcite, Medijdile, Zippeite, Voglianite, Uracouite, are other 

 uranium sulphates. 



Uranocircite is a hydrous barium-uranium phosphate. 



IRON. 



Iron occurs native, and alloyed with nickel in meteoric iron. 

 Its most abundant ores are the oxides and sulphides. It is 

 also found combined with arsenic, forming arsenides and 

 sulpharsenides ; with oxygen and other metals, as chro- 

 mium, aluminum, magnesium ; and in the condition of sul- 

 phate, phosphate, arsenate, columbate, silicate and carbon- 

 ate, of which the last is an abundant and valuable ore. 

 Its ores are widely disseminated. The oxides and silicates 

 are the ordinary coloring ingredients of soils, clays, earth and 

 many rocks, tinging them red, yellow, dull green, brown 

 and black. 



The ores have a specific gravity below 8, and the ordinary 

 workable ores seldom exceed 5. Many of them are infusible 

 before the blowpipe, and nearly all minerals containing iron 

 become attractable by the magnet after heating, when not 

 so before. By their difficult fusibility, the species with a 

 metallic lustre are distinguished from ores of silver and cop- 

 per, and also more decidedly from these and other ores by 

 blowpipe reaction. 



Native Iron. 



Isometric. Usually massive with octahedral cleavage. 



Color and streak iron-gray. Fracture hackly. Malleable 

 an d ductile. H. ±= 4 -5. Gr. = 7 -3-7 *8. Acts strongly on the 

 maornet. 



Obs. Native iron occurs in grains disseminated through 

 some doleryte, basalt, and other related igneous rocks ; and 

 in Greenland, in very large masses in such igneous rocks, 

 the largest weighing over a ton. It is suggested by J. 

 Lawrence Smith, that the iron was reduced by means of 

 carbohydrogen vapors, taken into the rock from carbonaceous 

 rocks passed through on the way to the surface. 



