OWEN'S DESCRIPTION OF TWO NEW MINERALS AND A NEW EARTH. 183 



In 1849 Dr. Shumard brought a soft, brittle, pale-green mineral, which was col- 

 lected from the cavities of an amygdaloid three miles above Kettle River, in 

 Minnesota, which has, when dried, much the appearance and consistence of this 

 silicate of magnesia from Lake Superior. This Kettle River mineral, when first 

 collected, was as soft as butter, but hardened by exposure. 



I also made an analysis of this mineral, but found it to contain a much smaller 

 quantity of magnesia, much larger per centage of alumina, more silica, and none of 

 this peculiar earth. The constituents are as follows : 



o f Silica, 52.7 



Matter insoluble in HCl, being silicates of 1 ai • _-tu i c -j c- on a 



, Mt g 0111V.4UC0 VL ^ J Alumina, with a trace of oxide of iron, 20.0 



alumina, magnesia and alkali, 85.2 1 I M ' 4. ^"i 



w» (^ Alkali and loss, .... 8.15 



Alumina, soluble 



in HCl, 



Oxide of iron, 



cc 



Magnesia, 



u 



Manganese, 



it 



Potash, 





Soda, 





Water, 





3.3 

 1.2 

 0.73 

 .9 

 .7 

 1.1 

 9 



This mineral does not agree exactly with the analysis of any mineral of which I 

 have seen an analysis. It comes nearest in its composition to a variety of Phillip- 

 site from Iceland, analyzed by Damour, except that magnesia replaces the lime in 

 Phillipsite : and this mineral would therefore be a magnesian harmotome. 



It differs, too, in its degree of hardness, from the Phillipsite, or lime harmotome. 



This magnesian harmotome from Minnesota decrepitates before the blow-pipe, and 

 fuses to a nearly colorless blebby glass, with a faint tinge of yellow. 



The analysis of this mineral gives a slight excess which ought probably to be 

 deducted from the alumina, which being bulky was very difficult to wash clean. 



It seemed to exist in the cells of the amygdaloids of Kettle River, in its nascent 

 state, and could be spread with a knife, just like the saponite mentioned by Alger, 

 who states that some of the miners of Brucksved tried to eat it as a substitute for 

 butter. 



