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



The material was pale red and granular, the matrix of frank- 

 linite grains. 



Ca 51-21 Al ___ 0-18 



Mg 0-24 F 45-85 



Fe 0-27 CI,Co 2 none 



Mn 0-09 



97-84 



Mr. Steiger remarks that the deficiency in the analysis is 

 doubtless due to fluorine. 



The manganese content is insignificant. If the total defici- 

 ency, 2*16 per cent, is calculated as fluorine, there is still slightly 

 less than is required to form RF 2 with all bases, but almost 

 exactly enough to satisfy the calcium. This suggests, but of 

 course does not prove, that the bases other than calcium are 

 present as impurities in the form of unknown compounds. 



Manganosite : Occurrence, Composition. 



This rare substance, known hitherto only from two Swedish 

 localities, was found in a single specimen in the Harvard 

 Mineralogical Museum. The specimen consists of a granular 

 aggregate of franklinite, zincite and manganosite. The latter 

 is in irregular grains showing cubic cleavage, dark green in the 

 mass, emerald-green in thin fragments. The material analyzed 

 contained traces of zincite and minute black films of manganese 

 oxide. The specific gravity was 5*364. 



1. Manganosite : analysis by George Steiger, IT. S. G. S. 



2. Same corrected for ZnO and Mn0 2 known to be present. 



1 2 



MnO._ __. 94-59 99-61 



Mn0 2 1-30 



ZnO v 3-41 



ll% t \ 0-26 0-27 



MgO 0-11 0-12 



H 2 0- 0-38 



HO+ 0-40 .... 



100-45 100-00 



The material is thus shown to be very nearly of the theo- 

 retical composition of manganosite, MnO. 



Zincite: Crystal Form. 



Measurements of natural crystals of zincite. are very few and 

 poor and the generally accepted axial ratio for the species is 

 based on^artificial crystals. The writer obtained measurements 



