PHYSIOGRAPHY. 197 



Specular Iron. 



Specular Iron, between which and the crystallized Specular Iron 

 there exists an uninterrupted transition. Among the varieties of Clay 

 Iron- Ore, the following may be considered as an appendix to the pres- 

 ent species, all of which are of a red color, but more or less impure, and 

 mixed with earthy substances, Reddle possesses an earthy, coarse slaty 

 fracture; it soils and writes, and maybe used as a drawing material. 

 Jaspery Clay Iron- Ore, has an even or large flat conchoidal fracture, 

 and a hardness which is considerable, if compared with other minerals of 

 a similar formation. Columnar and Lenticular Clay Iron- Ore are dis- 

 tinguished, the first by the columnar form, the latter by the flattish gran- 

 ular form of its particles of composition. 



2. Specular Iron is infusible before the blow-pipe, but melts with 

 borax, and forms a green or yellow glass, like pure oxide of iron. It is 

 likewise soluble in heated muriatic acid. 



3. Analysis. 



A _, t Varieties and Ox. of Ox. Si- ,. Alu- Wa- To- 



localities. iron. man?, lica. Lllrie - mina. ter. tal. 



BUCHOLZ. Micaceous Tron-Oro. . 100-00 . O'O . 0-00 . O'O . 0-00 . O'O. 100-00 



D'AUBISSON. Red Hematite. Framont. . 90-00 .trace. 2-00 . 1-0 . 000 . 3'0. 96-00 



" " " . 94-00 .trace. 2-00 .trace. 0.00 . 2.0. 98'00 



BUCHOLZ. Compact Red Iron. . 100-00 . 0-0 . 0-00 . 0-0 . 0-00 . 0-0. 100-00 



LAMPADIUS. Compact Red Iron. . 65-40 . 2'7 . 20-70? 00 . 9'3 .0-0. 98-10 



BUCHOLZ. Red Iron-Foam. . 100-00 . 0-0 . 00 . 0-0 . 0-0 . 0-0. 100-00 



HENRY. " " . 94-50.0.0. 4-25? . 1-25 . 00. 100-00 



The clay iron-ores, being more or less mixed with earthy substances, 

 vary in their contents, and several of their properties are dependent upon 

 the nature of these admixtures. Thus lenticular clay iron-ore is very 

 'rich, while the columnar variety contains hut little iron, and is produced 

 from nodoK of common clay, which have been converted by the influ- 

 ence of heat from burning coal seams, the one into columnar clay iron- 

 ore, the other into porcelain Jasper. 



4. It occurs most commonly in beds and veins in ancient rocks. Clay 

 iron-ore forms either by itself beds in secondary mountains, or it is in- 

 cluded in beds of clay in the shape of nodules or irregular masses. Spec- 

 ular Iron-Ore occurs in crystals among the rocks ejected by Vesuvius, 

 and lining the cavities and fissures of lava, where it seems to be a pro- 

 duct of sublimation. In beds, it is generally accompanied by other ores 

 of iron, several species of earthy minerals, as Epidote, Hornblende and 

 Augite, Calcareous Spar and Quartz. 



17* 



