IRON. 397 



LOCALITIES. 



This mineral was first found by Friesleben in some old mines in the neighbourhood of Frey- 

 berg in Saxony, and it appears to have been the result of the decomposition of some of the 

 ores of arsenic and iron. It is not constant in its composition, as the analysis of Klaproth, 

 quoted by Shepard, shows only the presence of oxide of iron, sulphuric acid and water. 



There is associated with the arsenical iron pyrites and scorodite found on Hopkins' farm 

 near Edenville in Orange, a substance which is probably identical with the mineral above 

 described. It occurs in the form of a dull or earthy coating of a chrome yellow, orange yel- 

 low or yellowish white colour, sometimes brown on the surface and yellow within. It adheres 

 to the tongue, and may be crushed by the nail. When heated, it gives out water and arse- 

 nious acid, and at length fuses into a dark brown or black scoria which is attracted by the 

 magnet. No sulphur or sulphuric acid seems to be contained in this mineral. I formerly 

 supposed it to be a compound of sulphur and arsenic. It is probably formed by the decompo- 

 sition of the arsenical iron pyrites. 



SPATHOSE IRON. 



[So named from its sparry appearance.] 



Feroxid^ carbonate. Hauy. — Spathose Iron. PhiUips. — Carbonate of Iron. CleaveUind sji^ Thomson. — Rhom- 

 bohedral Spany Iron. Jameson. — Brachytyper Parachroz-Baryt. Mohs. — Sidirose. Beudant. — Spathic 

 Iron. Shepard. 



'^,  Description. Colour yellow, white, brown and black. Streak 



white. It occurs regularly crystallized ; also massive and dissemi- 

 nated. The primary form is a rhombohedron, the faces of which 

 are sometimes curvilinear. Fig. 472. P on P' 107°. Cleavage 

 parallel with the sides of the primary. Fracture sometimes splintery. 

 Lustre brilliant or pearly. Translucent to opaque. Rather brittle. 

 Hardness from 3.5 to 4.5. Specific gravity from 3.30 to 3.90. 

 Before the blowpipe, it blackens and becomes magnetic, but does 

 not melt ; with borax, it becomes bottle-green in the reducing flame, 

 and yellow in the oxidating one. Difficultly soluble in acids, unless reduced to fine powder. 



Composition. Protoxide of iron 57.50, carbonic acid 36.00, oxide of manganese 3.30, 

 lime 1 . 25 {Klaproth). It is a carbonate of the protoxide of iron. Formula FeO . CO,. 



Geological Situation. Occurs in primitive and transition rocks. In the State of New- 

 York, it is almost always associated with specular iron ore. 



Uses. When abundant, this is a very valuable ore of iron. It is thought to be peculiarly 

 adapted to the manufacture of steel. 



