36 Phosphate of Uranium in the Tourmaline. 



" The mineral is one of the Uranium family, as you suggest- 

 ed, and appears to contain phosphoric acid and oxide of Ura- 

 nium, as essential constituents, only. In nitric acid it readily 

 dissolves, without effervescence ; the result of the solution 

 treated with ammonia, gives a yellow ammoniacal salt of ura- 

 nium. When the ammoniacal salt is treated with carbonate 

 of ammonia it dissolves, and in a solution of muriate of 

 ammonia can be precipitated as a white flocculent matter, re- 

 sembling the phosphate of uranium. The solution in nitric 

 acid gives with Ferrocyanate of Potash the characteristic 

 chesnut-brown precipitate of Uranium Salts." 



The quantity found was small ; there were however two or 

 three well defined cubic crystals, from two to three lines 

 diameter, and varying in color from straw-yellow to light 

 green. Some crystals exist in the red centre of the Tourma- 

 line, and are exposed on splitting the crystals ; others are on 

 the quartz and on the Albite forming the mass. 



Many of these Tourmalines are in a state of internal disin- 

 tegration ; the interior is then often found in a fibrous stale. 

 In the midst of, and attached to, the fibres, I have found sev- 

 eral crystals of this phosphate of uranium, probably existing 

 there originally, and not sharing in the decomposition of the 

 surrounding substances. 



I am not aware that this mineral has yet been noticed from 

 this locality, and believe it to be hitherto of very rare occur- 

 rence in the United States. 



The examination of these Chesterfield Tourmalines is ex- 

 tremely interesting. I have found two other substances 

 accompanying them, of species unknown to me, and differing 

 from any I possess ; these shall be examined at my leisure. 



The frequent abandonment of the study of Mineralogy for 

 that of the more imposing science of Geology, is much to be 

 regretted ; and I believe when the former shall be pursued 

 with the peculiar views of elucidating the processes of the 

 formation and consolidation of rocks of various mineralogical 

 composition, the actions by which crystalline deposits, inclu- 

 ding those in cavities, are produced, and particularly of inves- 

 tigating the changes, re-combinations and metamorphoses 



