W. P. Blake — Tourmaline of Crown Point, N. Y. 123 



Art. XY. — Tourmaline of Crown Point, JV. Y. • by ¥m. 



P. Blake. 



The tourmaline of Crown Point, Essex County, ]ST. Y., is 

 interesting by reason of its peculiar occurrence, association, 

 gem-like characters, color, and crystallization. It occurs in 

 the midst of the concretionary and investing form of phos- 

 phate of lime described by Dr. E. Emmons as eupyrchroite. 

 The locality, about a mile south of the Crown Point village, 

 was worked in the year 1852 to obtain the phosphate for the 

 manufacture of fertilizers but was soon abandoned. 



The material thrown out yielded many fragments of tourma- 

 line, light clove-brown in color, transparent and valuable as 

 gems. Fragments having terminal planes have recently been 

 submitted by me to Mr. John Marcus Blake of New Haven 

 for crystallographic study. He has drawn the accompanying 

 figure representing the antilogous 

 terminal. In the number and relative 

 size of the planes this closely resembles 

 the figure from Pose of the antilogue 

 pole of a crystal from Gouverneur, 

 N. Y.," but the cross-section of the 

 prism of the Crown Point crystals is 

 hexagonal rather than triangular, and 

 in this respect resembles the figure of 

 the crystal from Hunterstown, C. E.f 



Mr. Blake writes : 



"Pose's specimen from Gouverneur 

 had a greater development of the pris- 

 matic j)lanes m, which gives a triangular appearance to the 

 prismatic section, whereas these Crowm Point specimens show 

 an almost complete suppression of these m planes, while the 

 complementary m planes which come opposite the plane o, on 

 the antilogous pole, are here moderately developed, while they 

 do not show at all in Pose's drawing. These latter m planes 

 are, however, shown on drawings of crystals from Gouverneur, 

 N. Y., figs. 8, 9, 10, Dana's Mineralogy drawn by Farrington. 

 Here, also, the m planes first named are shown large, as in 

 Pose's drawing. 



The hexagonal section of the Crown Point specimens is 

 caused by the large development of the a planes. These 



* Dana's Mineralogy (E. S. Dana), 6th edit., p. 552, fig. 11. 

 f Ibid., 5th edit., p. 366, fig. 336. 



