PALLADIUM. 127 



per cent, platinum, and as malleable as the metal in ordi- 

 nary use, though somewhat more liable to tarnish, owing to 

 some of its impurities. Deville and Debray have perfected 

 this process, and have melted over 25 pounds of platinum 

 in less than three-quarters of an hour. In the process the 

 osmium present is oxidized and thus removed. 



Platin-iridium. Grains of iridium have been obtained at Nischne 

 Tagilsk, consisting of 76 - 8 iridium, and 19*64 platinum, with some 

 palladium and copper. A similar platin-iridium has been obtained at 

 Ava, in the East Indies. Another, from Brazil, contained 27*8 iridium. 

 55 "5 platinum, and 6 '9 of rhodium. 



IHdosmine. A compound of iridium and osmium from the platinum 

 mines of Russia, South America, the East Indies, and California. The 

 crystals are pale steel-grav hesagonal prisms ; usually in flat grains. 

 H.*=6-7. G. =19-5-21-1 'Malleable with difficulty. 



The composition varies. One variety, called Newjanskite, contains 

 iridium 46 - 8, osmium 49 3, rhodium 3 2, iron 0*7. Another, Sisser- 

 skite, iridium 25*1, osmium 74*9, and iridium 20, osmium 80. But 

 analysis affords also from 0*5 to 12 3 of rhodium, and 2 to 6 '4 

 of the rarer metal ruthenium, with traces usually of platinum, cop- 

 per and iron. The grains are distinguished by their superior hardness 

 from those of platinum, and also by the peculiar odor of osmium when 

 heated with nitre. Iridosmine is common with the gold of Northern 

 California, and injures its quality for jewelry Occurs sparingly in 

 the gold washings on the rivers I)u Loup and Des Plantes, Canada. 



The metal iridium is extremely hard, and is used, as well as rho- 

 dium, for points to the nibs of gold pens. Its specific gravity is 21*8. 



Laurite. In minute octahedrons. A ruthenium sulphide, with 3 

 per cent, of osmium. From platinum sands of Borneo and Oregon. 



Palladium. 



Isometric. In minute octahedrons. Occurs mostly in 

 grains, sometimes composed of divergent fibres. Color 

 steel-gray, inclining to silver- white. Ductile and malleable. 

 H. 4-5-5. G. =11-3-12-2. 



Consists of palladium, with some platinum and iridium. 

 Fuses with sulphur, but not alone. 



Obs. Occurs in Brazil with gold, and is distinguished 

 from platinum, with which it is associated, by the divergent 

 structure of its grains. It was discovered by Wollaston, in 

 1803. SeUnpaliadite, or Allopalladhim, is native palladium 

 in hexagonal tables from Tilkerode in the Hartz. It is re- 

 ported also from St. Domingo and the Urals. Porpezile 

 is palladium gold, or gold containing about 10 per cent, of 

 palladium ; three samples assayed at the Eio de Janeiro 

 mint yielding 11-1, 9 -75, and 7 -7 per cent, of palladium. 



