TRON. eal 
Johannite or Uranvitriol is a sulphate of uranium. It has a fine 
emerald-green color, and a bitter taste. From Bohemia. | 
Trogeritte and Walpurgite are uranium ars nates. Voglite and 
Inebigite are uranium carbonates. Johannite is a uranium vitriol ; 
Uranochatcite, Medijdite, Zippeite, Voglianite, Uraconite, are other 
uranium sulphates. 
Uranocircite is a hydrous barium-uranium phosphate, 
IRON. 
Tron occurs native, and alloyed with nickel in meteoric iron. 
Its most abundant ores are the oxides and sulphides. It is 
also fonnd 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 1s 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 
and ductile. H.=4:5. G.=7-3-7°8. Acts strongly on the 
magnet. 
Obs. Native iron occurs in grains disseminated through 
some doleryte, basalt, and other related igneous rocks ; and 
in Greenland, in very large masscs 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. 
