PHYSIOGRAPHY. 191 



Spathic Iron. 



It is sometimes possible to obtain from them by fracture the form of g, 

 bounded on all sides by faces of composition, without presenting a single 

 real face of cleavage. There is no distinct cleavage parallel to the face 

 of g. The saddle shape lenses are in part composed of several individu- 

 als nearly in parallel position, but the axes of which are slightly di- 

 verging. 



2. Before the blow-pipe, it becomes black, and acts upon the mag- 

 netic needle, but does not melt. It colors glass of borax green. It is 

 soluble with difficulty, and effervesces but little in nitric acid, particu- 

 larly if not reduced to powder. On being exposed to the air, it is gradu- 

 ally decomposed ; first the color of the surface becomes brown or black ; 

 afterwards the streak is changed into red or brown, hardness and sp. gr. 

 are diminished, and even the chemical constitution is altered, the whole 

 being converted into hydrate of iron. 



3. Analysis. 



By KLAPROTH. 



A botryoidal variety. A cleavable variety. 



Protoxide of iron - 63 75 - - - 57-50 



Carbonic acid - 34-00 - - - 36 00 



Oxide of manganese - 0-75 - - - 3-30 



Lime 00 - - - 1-25 



Magnesia 0-52 - 000 



4. Spathic Iron is frequently found along with compound varieties of 

 Calcareous Spar in beds in gneiss, mica slate, clay-slate and newer- 

 rocks ; sometimes with Limonite and Specular Iron, Heavy Spar, and 

 other species. It likewise occurs in metalliferous veinsTaccornpanied 

 by Galena, Fahlerz, Iron Pyrites, &c. More rarely, it occurs in the 

 cavities of trap rocks. 



5. The beds in which the varieties of the present species are found in 

 immense quantities in Stiria. Carinthia, and the bordering countries, 

 form connected tracts, which extend along the chain of the Alps, on one 

 side into Austria, and on the other into Salzburg. The celebrated Erz- 

 berg near Eisenerz, is situated in one of them At Freiberg, it is found 

 in silver veins. It is found with Tin-Ore, at Ehrenfreidersdorf in Saxo- 

 ny, Wheal Maudlin, St. Just, and other places in Cornwall. It is also 

 found, in more or less considerable masses, in Bohemia, Bayreuth, WUr- 

 temberg, Switzerland, France, Spain, and many other countries. 



A very considerable vein of Spathic Iron exists in the United States, 

 atRoxbury, (Conn.) which traverses in a vein of Quartz, a mountain of 



