488 Outlines of the Mineralogy and Geology 



SPECIES Il.—MJIGKETICK OXIBE OF JROM 



Magnetic Oxide of Iron, Cleaveland^ p. 482. Common Magnetic ironstone, 

 Jameson^ vol. n. p. 269. Idem, Kinvariy vol. ii, p. 158. Magnetic iron ore, 



Aikirif^. 113. 



External Characters. 



lis colour is greyisli black; sometimes tarnished yellowisli 

 brown. 



Its lustre is faintly glimmering. 



It is amorpiious. 



Tlie streak is similar^ but the powder is blackish grey. 



It Is hard. 



The fracture is fine grained uneven ; gome specimens show a 



straight foliated structure. 



It is brittle. 



It is easily frangible. 



The fragments are indeterminately angular, and not particu- 

 larly sharp edged ; sometimes the fragments are trapezoidal. 

 It affects the magnetick needle and possesses polarity. 

 Its specifick gravity is about 4.714. 



Chnnical Character* 



Before the blowpipe it decrepitates and fuses into a black slas. 



Geological Situation and Lccalify. 

 It occurs in a vein in Greenstone, at Woburn, where it is inti- 



mately connected with Sulphuret of Copper, 



