C. Palache — Mineralogy of Franklin Furnace, N.J. 185 



H.(A],Fe).C n Si li O„ 



with part of the lime replaced by a number of oxides. 



Datolite: Crystal Form. 

 Datolite has been known for some time from the Parker 

 shaft, Franklin Furnace, but crystals have not hitherto been 

 described from there. Complex crystals were found in a 

 specimen in the Harvard Collection on which were observed a 

 number of forms including several new to the species. In the 

 following list new forms are marked with an asterisk : 

 a (001) e (023) x (101) y (221) e' (ill) /: (241) k : (245) 

 c (100) M (011) *I (304) A- (111) a' (221) j : (243) 

 g (110) o (021) <£ (102) 0- (112) Q' (121) *d (263) 

 m(120) *q: (701) £ (101) Y- (223) p (211) *&• (475) 



Symbols and lettens after G-oldschmidt, Winkeltabellen. 

 The pyramid d (263), new to datolite, is present on all the 

 crystals with characteristic form. 



Cuspidine: Occurrence; Composition. 



The occurrence of this mineral, known hitherto solely from 

 Vesuvius, at Franklin Furnace is established by the following 

 analysis, for which the writer is indebted to Dr. C. H. Warren. 



The material, which occurred with nasonite, was isolated by 

 hand-picking and heavy solution and analyzed by him at the 

 time (1899) Pen field and Warren were working on nasonite 

 and other peculiar silicates from the Parker shaft. At the 

 time no satisfactory interpretation of the analysis was hit upon, 

 the identity of the mineral remained hidden, and, all the mate- 

 rial having been used in analysis, the matter was put one side. 

 The material analyzed consisted of glassy white crystal frag- 

 ments of specific gravity between 2*965 and 2*989. 

 I. Analysis of cuspidine, C. H. Warren, 1899. 



II. Same recast and recalculated to 100 per cent after substi- 

 tuting equivalents of Ca for Mn, K, and Na. 





I 





II 



Molecular Ratio 



Si0 2 



32-36 



Si 



I'5-IO 



•539 1 



CaO 



61-37 



Ca 



44-63 



1-115 2-05 



MnO 



Na 2 



0-71 

 0-48 



F 



O" 



9-05 

 31-22 



;H\\ 2-189 4-06 



K 2 



0-27 









F 



905 











104-24 





Less O = F 2 



3-81 









100-43 



