IRON. 



393 



In Connecticut, the crystallized variety of magnetic iron pyrites occurs at Monroe and in 

 Trumbull. 



Fig. 464. 



WHITE IRON PYRITES. 



Radiated Sulpburct of Iron, a variety of Iron Pyrites. Ckavdand. — Fer Sulfure Blani-. Tlaiiy. — White Iron 

 Pyrites. Phillips and Shepard. — Radiated Pyrites. T/wmson. — Prismatic Iron Pyrites. Jameson. — Pris- 

 matischer Eisen Kies. Mohs, — Sperkise. Bciidunt. 



Description. Colour pale bronze-yellow, sometimes inclining to steel-grey or brass-yellow. 

 Streak greyish black or brownish black. It occurs regularly crystal- 

 lized ; also stalactitic, reniform and botryoidal. Primary form a right 

 rhombic prism. Fig. 464. M on M' 100° 2'. Cleavage parallel with M, 

 rather perfect. Fracture uneven. Lustre metallic. Opaque. Brittle. 

 Easily frangible. Hardness from 6.0 to 6.5. Specific gravity from 

 4.67 to 4.85. Before the blowpipe, the sulphur is driven off, and 

 oxide of iron remains. It is sometimes particularly liable to decom- 

 position. The difference in the crystalline form, however, is a more sure mark of distinction. 

 It is only slightly acted on by muriatic acid. 



Varieties. When this mineral occurs in radiated concretions, it is called Radiated Pyrites ; 

 when it is found in spear-shaped twin or triple crystals, it is named Spear Pyrites ; ,a.nd 

 when the crystals are aggregated so as to have the form of the crest or comb of a cock, it 

 forms the Cockscomb Pyrites. 



Composition. Iron 45.66, sulphur 54.34 (H'a/c/?ef/). Iron 45.07, manganese 0.70, sul- 

 phur 53.35, silica 0.80 (Bcrzelius). The constituents are therefore the same as that of the 

 preceding, and it differs from it only in its specific gravity and crystalline form. 



Geological Situ.ation. This mineral is found in rocks similar to those which contain the 

 last mentioned species. 



localities. 



Orange County. The crystallized variety occurs two and a half miles southeast of the 

 village of Warwick, in a vein of feldspar in granite, associated with zircon and tourmaline. 

 The crystals are somctiiues an inch in length, of a white and pale bronze-yellow coloiu-, and 

 striated longitudinally. They are less hard than those of common iron pyrites, and decomjiose 

 easily. Before the blowpipe, they give out the odour of sulphur, and melt into a globule which 



is black and magnetic when cold. 

 Crystals of the form represented 

 in Fig. 465 have been found here, 

 and also the coiupound one made 

 up of five individuals. Fig. 466. 

 M on M' 106=5 2'; P on c 160=> 

 48'; a on c 141° 30'. 



Fig. 405. 



50 



