PHYSIOGRAPHY. 



Native Iridium Native Iron. 



rein deposits; those of Burke, Lincoln, and Rutherford, are mostly allu- 

 vial mines. A single mass of Native Gold was found in Cabarras county 

 that weighed twenty- eight pounds.* Several vein mines in the neigh- 

 borhood of Fredericksburg, (Va.) have afforded fine specimens of Native 

 Gold, traversing white Quartz. 



NATIVE IRIDIUM. Iridium Sclerone-Metal. 



Primary form. Rhomboid. 



Secondary form. Six-sided prism, combined with two 

 isosceles six-sided pyramids. 



Cleavage, perpendicular to the axis. Grains. 

 Lustre metallic. Color pale steel-grey. Opake. 

 Brittle. Harder than Platina. Sp. gr. =19-5. WOL- 



LASTON. 



1. If melted with nitre, it becomes black; but again acquires both its 

 color and lustre, if heated with charcoal. It is not dissolved by nitro- 

 muriatic acid. It is an alloy of iridium and osmium. 



2. It occurs in South America, accompanied with Native Platina. 



NATIVE IRON. Iron Sclerone-Metal. 



Primary form. Regular octahedron. 



Cleavage, visible, parallel with the primary form, the 

 crystal being traversed by natural joints, separating it into 

 laminae, which project and recede, so as to leave oblique 

 angled cavities of greater or less extent on all the faces. 

 The crystal is partially oxidated upon the outside, and be- 

 tween the laminae. Fracture hackly. 



Lustre metallic. Color iron-grey. Streak shining. 

 Strong action on the magnet. 



* The stream-mines of the U. States, have yielded about $6,000,000. 

 Three deposit mines in Georgia have afforded $500,000. 



