MINERAL RESOURCES OF THE STATE OF NEW YORK 27 



and jigs until the phosphorus content is raised to at least 8-9 per 

 cent, corresponding to 40-45 per cent of bone phosphate. As 

 illustrative of the effect of the process the following analyses are 

 of interest, although not strictly representative of present day 

 conditions. No. i refers to the crude ore, no. 2 to second grade 

 apatite concentrates and no. 3 to first grade apatite concentrates. 



123 



Iron 59.59 12.14 3-55 



Phosphortis ■. ; i . 74 8 . 06 12.71 



Bone phosphate equivalent 40 • 30 63 . 55 



The concentration at present is carried only so far that the 

 phosphate content reaches 40 to 45 per cent. The product is finely 

 ground and admixed with bariiun sulphide, constituting an agri- 

 cultural fertilizer which is sold as " barium-phosphate." In its 

 properties the material is analogous to basic slag which has been 

 extensively employed for fertilizer in Europe, and it combines the 

 fertilizing value of phosphorus with an alkaline reaction that 

 promotes nitrification. 



There are no other deposits of magnetite in the State, so far as 

 known, that contain enough apatite to justify similar operations 

 for its recovery and utilization. 



The occurrence of apatite in the crystalline limestones of the 

 State may be noted, but rather on account of their mineralogical 

 interest than of possible commercial importance. Among the 

 localities which afford good crystallized specimens are Gouverneur 

 and Hammond, St Lawrence county; Natural Bridge, Lewis county; 

 and Amity, Orange county. The contact zones between intrusive 

 granites and limestones are frequently characterized by the presence 

 of apatite. 



A phosphate mineral called eupyrchroite, an amorphous calcium 

 phosphate closely resembling apatite, has been produced on a small 

 scale in years past. The single known occurrence is just south of 

 Crown Point, Essex county, near the shore of Lake Champlain. 

 It is mentioned in the reports of the First Geological Survey, and 

 mining operations were carried on for a time about the year 1850 

 with the production of 100 tons or so of the material for use as 

 fertilizer. The usual form of the substance is a massive aggregate, 

 sometimes showing concretionary or botryoidal structure, of bluish 

 to grayish color. When heated it gives a phosphorescent green 

 light. An analysis by Charles T. Jackson published in the American 

 Journal of Sci ence^ showed 92.94 per cent of tri-calcium phosphate. 



1 Series 2, v. 12, 1851. 



