Mineralogical Notices, 



211 



t 



w 



4 



mon earths and oxyds, established.'' [We may mention that the 



most common form closely resembles that of garnet, and the 



mineral had been referred to this species, which it externally 



resembles. The angle of the pyramid is given at 122^ to 124*^; 



but the surfaces are so irregular that the measurements are un- 

 certain,] 



7. Eumajiite^ (ibid, p. 317). — From Chesterfield, Mass., at the 

 albite locaUty. Only a single minute crys- 

 tal less than a grain in weight is known. 



Form trinietric ; M : M = 123^. M : e' 

 136^ 



; 



J 



e'; e 



151^30': e':e'' 



e: a = 127Q 40^ 



3 



M 



? 



e 



e 



118^ 



159^30' 



118^ 30 



J 



? 



Eumanite. 



Topaz gives 



e' : a = 127° 30' ; a: = 144^20'; c:o = 128° 

 20'; e' : o = 156°30'; surface M rather im- 

 perfect and not very lustrous ; the other faces 

 brilliant. Color blackish-brown, resembling 

 certain crystals of tin ore. Translucent; 

 color by transmitted light deep red, like al- 

 tnandine garnet. H. above 6. 



[The crystal of eumanite has closely the 

 form of topaz, even to the general charac- 

 ter and position of the planes on the sum- 

 niit, and is near figure 393 in Dufrenoy's 

 Mineralogy ; the angles also are nearly identical. 

 M : M=-. 124° 19' ; and if M on e in eumanite is 118°, it will give 

 124° for M : M in eumanite— M, M, it should be noted, are the 

 least histrous faces of the crystal; M : e'=135o 59' (136° in 

 eumanite.) The mineral must therefore be closely isomorphous 

 with topaz, if not identical with it, and some other characters are 

 needed to show that the latter supposition is not true, although 

 so peculiar in its color. In the figure, the edge o' : e" on the 

 tight is parallel to the edge e" : e", but not so that on the left ; 

 we cannot say which is right.] 



8. Corundophilite, (ibid, p. 318). — Occurs with corundum near 

 Asheville in Buncombe cotinty, N. Carolina, in imperfectly stellate 

 groups, and also spreading out in laminae between layers of co- 

 rundum. A single crystal, exceedingly minute and less than |th 

 of a grain in weight, was monoclinic and gave the angles M : M 

 about 120° ; P : M = 97° 30' and 82° 30'; P(OP) : ocP'x =88° 

 to 89° ; P(OP) : mP'x = 122° 30'. Cleavage basal, perfect ; also 

 in traces parallel with M and the shorter diagonal of P. Lustre of 

 cleavage faces commonly pearly. Color dark leek-green, passing 

 into gray and greenish black ; streak like the color. Thin \^m- 

 ina flexible, but less so than talc. B.B. affords a little moisture 

 in a glass tube ; alone instantly turns black, and without phospho- 

 rescence. Melts at the extremity to a shining black globule ; 

 ^ith borax, forms readily with eflervescence a clear bottle green 



