196 PHYSIOGRAPHY. 



Specular Iron. 



smooth faces, while the reniform surface of the curved la- 

 mellar compositions is rough, and obtained with more diffi- 

 culty, by separating the particles, than the first. Massive : 

 composion, 1. Columnar, generally imperfect, thick, and 

 diverging from common centres. 2. Granular, and often 

 impalpable ; sometimes very distinct and easily separated ; 

 often, however, they are strongly coherent : if they are im- 

 palpable, their lustre decreases, their color becomes red, 

 and the fracture even, uneven, or flat conchoidal. 3. La- 

 mellar, joined in the face of o, thick and variously bent ; 

 sometimes, however, they are so thin, that they allow blood- 

 red light to pass ; if they are still thinner, their color be- 

 comes red altogether, and their lustre imperfectly metallic ; 

 the faces of composition are often irregularly streaked. 

 When the cohesion among the particles is diminished, the 

 lamellar varieties become scaly and glimmering, the granu- 

 lar ones earthy and dull. Pseudornorphoses in the shape 

 of Calcareous Spar, Fluor, &c. 



1. Owing to a want of attention to the simple and compound state of 

 he contents of the present species, has arisen its subdivision into two 

 species by the majority of mineralogists; viz. into Specular Iron- Ore 

 and Red Iron- Ore. Specular Iron contains all the simple varieties, and 

 those of the compound ones which have not lost their metallic appear- 

 ance by the too small size of their component individuals. Those in 

 thin lamellar compositions have been called Micaceous Specular Iron, 

 while the rest form the Common Specular Iron. Those varieties 

 which have lost their metallic appearance, are included within the Red 

 Iron-Ore, divided into Fibrous Red Iron or Red Hematite, which oc- 

 curs in reniform and other imitative shapes, and consists of columnar 

 particles of composition ; into Compact and Ochrey Red Iron, which are 

 massive, and consist of impalpable, granular individuals, more or less 

 firmly connected; and into Scaly Red Iron, or Red Iron- Foam, consist- 

 ing of very small scaly particles, which in most cases are but slightly 

 coherent. This variety is in immediate connexion with the micaceous 



