iron. 179 



72*4=100. Infusible before the blowpipe. Yields a yellow 

 glass when fused with borax in the outer flame. 



Diff. The black streak and strong magnetism distinguish 

 this species from the following. 



Obs. Magnetic iron ore occurs in extensive beds, and also 

 in disseminated crystals. It is met with in granite, gneiss, 

 mica schist, clay slate, syenyte, hornblende and chlorite 

 schist ; and also sometimes in limestone. 



The beds at Arendal, and nearly all the Swedish iron ore, 

 consist of massive magnetic iron. At Dannemora and the 

 Taberg in Southern Sweden, and also in Lapland at Kurun- 

 avara and Gelivara, there are mountains composed of it. 



In the United States it constitutes extensive beds, in Ar- 

 chaean rocks, in Warren, Essex, Clinton, Orange, Putnam, 

 Saratoga and Herkimer counties, New York; and in Sussex 

 and Warren counties, in New Jersey. Smaller deposits occur 

 in the several New England States and Canada. Also found 

 at Magnet Cove, in Arkansas ; in California, in Sierra 

 County, and elsewhere. It exists with hematite in the Iron 

 Mountains of Missouri. 



Masses of this ore, in a state of magnetic polarity, consti- 

 tute what are called lodestones or native magnets. They are 

 met with in many beds of the ore. Siberia and the Hartz 

 have afforded fine specimens ; also the Island of Elba. They 

 also occur at Marshall's Island, Maine; also near Providence, 

 Rhode Island, and at Magnet Cove, in Arkansas. The 

 lodestone is called magnes by Pliny, from the name of the 

 country, Magnesia (a province of ancient Lydia), where it 

 was found ; and it hence gave the terms magnet and mag- 

 netism to science. 



Franklinite. 



Isometric. In octahedral and dodecahedral crystals. Also 

 coarse granular massive. Color iron-black ; streak dark 

 reddish-brown. Brittle. H.=5-5-G*5. G. =4*85-5 1. Usually 

 is attracted by the magnet. 



Composition. General formula like that of magnetite, 

 PiR 4 , but having zinc and manganese replacing part of the 

 iron, as indicated in the formula (Fe, Zn, Mn) (Fe,Mn)0 4 . 

 A common varietv corresponds to Fe 2 3 67*6, FeO 5 - 8, Zn 

 6 9, Mn 9-7 = 100. 



B.B. with soda on charcoal a zinc coating is obtained ; a 



