C. Palache — Mineralogy of Franklin Furnace, JV. J. 117 



Art. XIII. — Contributions to the Mineralogy* of Franklin 

 Furnace, W. J.; by Charles Palache. 



The purpose of this paper is to present in brief form some 

 of the more interesting results obtained in the study, con- 

 tinued through several years, of the minerals of Franklin 

 Furnace, Xew Jersey. The complete results of the study will, 

 it is hoped, appear soon in monograph form, but it seems desir- 

 able to place on record without further delay the chemical 

 analyses made for the most part in the laboratory of the Geo- 

 logical Survey. These analyses are either of minerals not 

 before recorded from this locality or of species concerning 

 which our information is in complete. With these are also 

 included crystallographic notes on a number of species and a 

 list of additional minerals whose presence at Franklin Furnace 

 has not hitherto been recorded. 



Arsenopyrite : Crystal Form, Composition. 



Brilliant crystals of arsenopyrite up to an inch in length 

 were found in several of the limestone quarries at Franklin 

 Furnace in 1905. They are associated with pyrite, pyrrhotite, 

 spinel, humite, tourmaline and phlogopite. The crystals are 

 completely developed, showing besides known forms the new 

 pyramids (532), (112), (113), and (132), the first present on all 

 crystals and characteristic for the locality. 



The following analysis by E. C. Sullivan, U. S. G-. S., was 

 made of selected crystal fragments : 



Eatio 

 Fe 32-48 -581 



I 



Co.- 1-16 -02 f 



As 48-72 -650 1*08 



S 18-80 -587 -98 



The ratio shows a normal composition. The presence of 

 cobalt is interesting ; it has been shown by Kraus & Scottf to 

 be present in about the same proportion in pyrite crystals in 

 the same limestone. Tests for cobalt made on the associated 

 pyrrhotite showed no trace of this element and hardly more 

 than a trace of nickel. 



Fluorite : Composition. 



The following analysis of fluorite by G-. Steiger, XL S. G-. S., 

 was made in the belief that it was a manganiferous variety. 



* Published by permission of the Director of the U. S. Geological Survey, 

 f Zeitschr. fur Kryst., xliv, 144, 1907. 



