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ART. XIX. — Description of two New Minerals and a New Earth. 

 By David D. Owen, M. D. 



While examining, in the summer of 1848, the North shore of Lake Superior, situated 

 in Minnesota, between Pigeon Point and Fond du Lac, particularly in the vicinity of 

 Baptism River, I observed a peculiar, soft, green mineral diffused in the amygdaloidal 

 traps. Though not in large masses, this mineral was so abundantly disseminated in 

 some of these rocks that the least blow of the hammer indented the rock and left a 

 whitish green mark from the easily crushed particles of the soft green mineral in 

 question. 



In the winter of the same year I undertook a chemical analysis of the mineral, and 

 repeated it on several varieties in the year following. 



The result showed it to be essentially a hydrated silicate of magnesia, and what 

 appeared to be a new earth, intermediate in its properties between magnesia and 

 manganese. 



The color of this mineral when pure is of a pale yellowish green : consistence and 

 hardness about that of wax. Heated in a matrass it gives off water. Heated strongly 

 alone in the forceps it whitens, but does not exfoliate ; tinges the outer flame slightly 

 green. In thin splinters it fuses on the edges. With borax it dissolves with difficulty 

 into a transparent bead, which has a greenish tinge when hot. With soda it dissolves 

 but very partially and very slowly. Heated with nitrate of cobalt hardly any color 

 is perceptible. Fused with four times its weight of carbonate of soda and potash in 

 a platina vessel it gives a white enamel, tinged on the edges only of a light blue. 

 Some specimens of this mineral effervesce distinctly with acids ; but this is always 

 from impurities. The pure varieties contain no carbonic acid. Specific gravity 

 2-548. It has not been found crystallized. 



Treated with hydrochloric acid, chlorine is evolved, and the greater part of the 

 constituents, except silica, dissolved. 



^ After the separation of the silica and the greater part of the magnesia, there invariably 

 remained a whitish mass, tinged slightly of a reddish yellow or flesh color, which had 

 a tendency to darken in the air; this amounted to 18 or 19 percent. When this was 

 dissolved in just sufficient hydrochloric acid to take it up, and afterwards boiled with 

 excess of caustic potash, 4-6 per cent, of alumina separated, leaving about 13.5 of matter 

 quite insoluble in that reagent ; of this 1-5 per cent, was peroxide of iron, and about 

 12 per cent, the new earth above alluded to, slightly contaminated with magnesia. 



