TITANIUM. 



431 



ILMENITE. 



[From the place where it was first found, near Lake Ilmen, in Siberia.) 



Iliuenitc. Phillips and Thiunsm. — Axotomcs Eiscn-Erz. Mahs. — Acclivnitc (ujip. to Polymignite). Bev.- 

 danl? — Mongit. Mohs, App. ? — Criclituiiilo. Slupard. 



Fig 516. 



Description. Colour brownish or iron-black. Streak black. 

 It occurs crystallized and massive. The form of the crystals 

 is the same as that of specular iron. Primary a rhombohe- 

 dron. Fig. 516. P on P 85° 59'. Cleavage perfect parallel 

 to a (sec Fig. 517). Fracture conchoidal. Lustre imperfect 

 metallic. Translucent. Brittle. Hardness from 5.0 to 5.7. 

 Specific gravity from 4.40 to 4.80; 4.77 to 4.81 {Thom- 

 so)i). It slightly afTccts the magnetic needle. Before the 

 blowpipe, thin edges are rounded, but it does not fuse ; with 

 fluxes, it behaves like oxide of iron. When in fine powder, 

 it is soluble in hot concentrated muriatic acid. 



Composition. Spccwwn from the Ural monntains — Titanic acid 46.67, jieroxide of iron 

 11.71, protoxide of iron 35.37, protoxide of manganese 2.39, magnesia 0.60, lime 0.25, 

 oxide of chromium 0.38, silica 2.80 {Mosander). According to Kane, the formula is 

 FeO.TiO,. 



Geological Situ.\tion. It occurs in granite, serpentine and white limestone, and is some- 

 times associated with rutile, and at others with magnetic iron ore. 



There is still some confusion in regard to this mineral, arising in part from the difficulty 

 which attends the accurate analysis of the compounds of titanium, and in part also from the 

 fact that minerals which are nearly identical in composition, having been found at different 

 localities, have received different names. No positive opinion, however, can at present be 

 expressed on this subject. It is believed that the Crichtonile of Shcpard is identical with 

 Bmenite ; and perhaps the same is true of the Crichtonite of Count Bournon, and of some of 

 the other minerals in which titanic acid is combined with the oxides of iron. 



localities. 



The most remarkable localities of ilmenite are in the towns of Warwick and Monroe ni 

 Orange county. One of these is about a mile south of the village of Amity. It occur.s here 

 in crystals of various sizes, sometimes an inch in diameter, imbedded in a dark coloured ser- 

 pentine. The forms are similar to those of specular iron ore, for which this mineral was 

 mistaken. It may, however, be distingushed by its colour, streak, and diminished specific 



