IRON ORES. 241 



ilmenite. — Titanic iron. 



In crystallization near specular iron. R : R=85° 59' 

 Often in thin plates or seams in quartz ; also in grains. 

 Crystals sometimes very large and tabular. 



Color iron-black ; streak metallic. Luster metallic 01 

 Bubmetallic. H=5 — 6. Gr= 4*5 — 5 ; acts slightly on the 

 magnetic needle. 



Composition : oxyd of iron, with a variable proportion of 

 titanic acid or oxyd of titanium. Infusible alone before the 

 blowpipe. 



Crichtonite, ilmenite, menaccanite, hystatite, and iserine, 

 are names of some of the varieties of this species. The hys- 

 tatite variety includes the washingtonite of Professor Shepard. 

 Octahedral and cubic crystals of this mineral have been found 

 with titaniferous sand, which are supposed to be pseudo- 

 ■norphous. 



Dif. Near specular iron, but differs in the less luster of 

 its crystals, and its metallic streak. 



Obs. Crystals an inch or so in diameter occur in War- 

 wick, Amity, and Monroe, Orange county, N. Y. ; also near 

 Edenville and Greenwood furnace ; also at South Royalston 

 and Goshen, Mass. ; at Washington, South Britain, and 

 Litchfied, Conn. ; at Westerly, Rhode Island. 



Uses. Of no value in the arts. 



chromic iron. — Chromate of Iron. \VHM 



Monometric. In octahedral crystals, without distinct clea. 

 vage. Usually massive, and breaking with a rough un- 

 polished surface. 



Color iron-black and brownish-black ; streak dark brown. 

 Luster submetallic ; often faint. H = 5*5. Gi=4*3 — 4*5. 

 In small fragments attractable by the magnet. 



Composition : green oxyd of chromium 60*0, protoxyd of 

 iron 20*1, alumina 11*8, magnesia 7*5. The alumina and 

 magnesia are variable. Infusible alone before the blowpipe. 

 Fuses slowly with borax to a beautiful green globule. 



Dif. The little luster of this ore on a surface of fracture 

 is peculiar ; also its fine green glass with borax, which dis- 

 tinguishes it from ores of iron and other metals. 



Describe titanic iron. Of what does it consist ? How does it differ 

 "rom specular iron t What is the appearance of chromic iron 1 its com- 

 position 1 How is it distinguished from other ores? 



