URANIUM. 81 



Bellmetal Ore (sulphide of tin). 



A rare ore, found massive and crystallized in cubes. 

 Colour steel grey. 

 Streak black. 

 Structure brittle. 

 H._ 4; S.G. 4-3 to 4-6. 

 Composition 27 percent, tin; copper, iron, and sulphur. 



Soluble in aqua regia. 



Veins of tin ore traverse granite, gneiss, mica, slate, 

 rhyolite, &c. 



Tinstone is frequently scattered about country rock near 

 the walls of a lode. 



In Cornwall the lodes generally run east and west, and 

 the average dip is 70 ; some also run across these. The 

 ore is also found as a series of small veins in friable granite ; 

 also in masses, and as stream tin, as well as in veins between 

 certain rocks and parallel to their beds. The true vein* 

 traverse granite and killas. In Queensland tin is obtained 

 from a deposit, and also from lodes through granite rocks. 

 In Tasmania from deposits and from lodes in a porphyritic 

 rock In New South Wales quartz veins carrying tin ran 

 through granite. The alluvial deposits of the Malay Archi- 

 pelago are doubtless derived from veins in granite, and so 

 are those in Burmah. 



URANIUM. 



Uranium in a mineral can be known by treatment with 

 microcosmic salt before B.F., the cold beads being of a green 

 colour (thus distinguishing it from iron) ; with borax in 

 O.F. the cold bead is yellowish (thus distinguishing it from 

 chromium). The principal ore is the oxide (often impure) 

 Pitchblende (one of the minerals containing the 



wonderful metal Radium). 

 Colour usually blackish. 

 Streak often blackish-brown. 

 H. less or more than 5 ; S.G-. less or more than 6. 

 The powdered mineral boiled in nitric acid is dissolved ; 

 and, if ammonia is added to the solution, a yellow precipi- 

 tate results. Pitchblende may contain more than 60 p.c, 

 of uranium oxide. 



