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 o? 

 submetallic. 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 iserinc^ 

 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. 



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. Gr = 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 1 How does it differ 

 "rom specular iron ? What is the appearance of chromic iron 1 its coir 

 position 1 How is it distinguished from other ores : 



