50 W. T. SchaUer — Natramblygonite, a New Mineral. 



The ratios yield the formula P,0 5 .Al a O I .(Na,Li\0.(H,0,F 1 ), 

 which may be written more simply AlNa(OH)P0 4 , with the 

 Na partly replaced by Li and the (Oil) by F. The ratios for 

 water and fluorine are a little high, but this is probably to be 

 ascribed to the difficulty of the fluorine determination. It is 

 worthy of note, however, that the ratios for water and fluorine 

 are also all high in Penfield's analyses of amblygonite.* The 

 relations of natramblygonite to amblygonite are clear, the first 

 being essentially the soda mineral and the second the lithia 

 one. 



Natramblvgonite, Na[Al(OH,F)]P0 4 . 



Amblygonite, Li [Al (OH,F)] P0 4 . 



Nothing was seen which would indicate that the new mineral 

 here described was originally the lithium compound which 

 was afterwards changed to the sodium one. The alteration of 

 amblygonite, described by Carnot and Lacroixf. yielded the 

 mineral morinite which contains lime and soda withoiit any 

 lithia and much more water and fluorine than was present in 

 the amblygonite. 



Chemical Laboratory, 



U. S. Geological Survey. 



* Penfield, S. L. On the Chemical Composition of Amblygonite ; this 

 Journal, 3d ser., vol. xviii, pp. 295, 1879. 



f Carnot, A., and Lacroix, A. The Chemical Composition of Morinite; 

 Bull. Soc. franc, mineral, vol. xxxi, 1908, p. 149. 



