Arizona citizen., 1879-10-18
THE CITIZEN.
SATCRbAY. OCToBER IS. 1879
RiatinUm

Platinum.
 We are permitted to make the fo
 lowing extracts from the reply of Pro
 B. Salazar, of this city, to the inaui
 ies of Mir Edison on the subject C
 platinum in Arizona. The hints give
 may be Of value to the hundreds n
 prospectors who are searching up an
 down our mountains and valleys:
 Metallic platinum, the only plafi
 mum ore, is found Tn grains of differpn
 sizes, in quantities worth extracting exclusively in placers, in deposits r
 secondary origin. Asan impregnaticr
 of entire mountains or lodes it ha
 been found in the Scrpentines anC GreenstOnes of the Ural Mountains e
 Russia and in Greensboro veins will gold in New Granada. But this raro occurrence is valuable only 10 the geol ogist and mineralogist The prospec. tor should look for platinum only ir placers. As companions and revealer, of platinum, there are nearly alwav found chrome, magnetic and titani iron, serpentine, corundum, spinell, gold, diamonds and other precior stones. II is strongly probable tha' serpentine is the mother rock of plafi nun, and whenever serpentine chronic iron are found in placer platinum may be expected Platinum grains are usually separated from ih gold by hand; but when the conccl trations are very fine they are subiecte, 10 amalgamatiOn; the quicksilver ar Joys only with the gold, and the anal gam can easily be separated from thr platinum. In the United Stares plati nun has been found in the gold placer of North Carolina, California and Or, gon."
 Platinum grains behave variouslv when treated with aquaregia. Save the softer ones, are dissolved entirely or partially, the harder grains are vervI little or not at all affected by the acid. They are always alloyed with the plat. mum metals. Pure platinum has steel gray color, very little luster hardness of 9 10 6, and is nearly a. ductile as gold. It's specific gravity is 17.5 to IS, being less than thar of gold but when welded, compressed or melt cd its specific gravity 21is greater than that of any of the metals except ore. When heated it can be welded like iron. It does not melt in the common metallurgical fires. but does not melt very readily when heated in lime cru. cihles with oxyhydrogen gas at 2OOOI I deg. c. Ii is soluble in warm hvdrc- ehloric nitric acid. The yellow solu. ion of chloride of platinum gives :; with ammonia a precipitate Of chloride ., 'f ammonium-platinum which can a DC converted into platinum sponge by I leating. C The value of pure platinum as . ompared with the other precious met. Is Is expressed by the following pro. a silver l, platinum 8. gold 15." a Although it is not known 10 me- ,, hat platinum has been found in Uni, T 'erritory, il must be admitted that all m be possibilities of its occurrence ex- cl t here, as all our alluvial soils are cry abundant in gold placers, and ser entine and cromic iron have been 'und in many of our mountain ranges rma 70 nd ought 10 exist also in our serond. W, y alluvial deposits. As our placers F. ave moi been thoroughly explored for "r atinum hy scientific men. and only few of the best paying gold placers SO i've been temporarily worked, ii i, ve 't unreasonable to expect that plat to um in paying quantities may be dis VI vered in Arizona at no distant day"