OADER IX. NATIVE PLATINA. 441 



5. The use of hexahedral Gold is in many respects analo- 

 gous to that of hexahedral Silver, and perhaps even more 

 extensive. 



GENUS VIII. PLATINA. 

 1. NATIVE PLATINA. 



Native Platina, JAM. Syst. Vol. III. p. 49. Man. p. 264. 

 Native Platina. PHILL. p. 324. Gediegen Platin. 

 WERN. Hoffm. H. B. III. 2. S. 7- Polyxen. HAUSM. 

 I.S.97. Gediegen-Platin. LEONH. S. 1.74. Platinenatif 

 ferrifere. HAUY. Traite', T. III. p. 368. TabLcomp. 

 p. 72. Traite', 2de Ed. T. III. p. 226. 



Irregular forms, grains. Surface uneven, some- 

 times worn off by attrition (pebbles). 



Cleavage none. Fracture hackly. 



Lustre metallic. Colour perfect steel-grey. Streak 

 unchanged, shining. 



Ductile. Hardness =4-0 ... 4-5. Sp. Gr. = 

 17-332, rolled masses. 



OBSERVATIONS. 



1. Native Platina generally contains a little iron. It is 

 accompanied besides by indium, osmium, rhodium, palla- 

 dium, and also by copper, chrome, and titanium. It is 

 very refractory, and soluble only in nitro-muriatic acid. 



2. The original repositories of native Platina are not 

 known, it having hitherto been found only in pebbles 

 and grains, generally small, but sometimes upwards of a 

 pound and a half in weight. It is accompanied by pyra- 

 midal Zircon and some other gems, also by octahedral 

 Iron-ore, hexahedral Gold, and native Indium and Pal- 

 ladium. 



3. Native Platina is principally found in South America, 

 in the provinces of Choco and Barbacoas ; also at Matto 

 Grosso in Brazil. It has also been found in St Domingo. 



