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CONTENTS. 



Page. 



THE MINERAL RELATIONS op FERBERiTE, by Frank L. Hess 7 



Geography and production 7 



Characteristics of the ferberite 8 



Geography and geology of the Boulder district 8 



Occurrence, vein systems, and relations 9 



Characteristics of the ore 10 



Minerals associated with the ferberite 12 



Adularia 12 



Calcite 12 



Chalcedony , 12 



Chalcopyrite 12 



Galena 12 



Gold and silver 12 



Hamlinite (?) 14 



Hematite (specular) 15 



Limonite 16 



Magnetite 17 



Molybdenite 17 



Opal 17 



Pyrite 17 



Quartz 17 



Scheelite 17 



Sphalerite 17 



Sylvanite 17 



Spectroscopic examination 18 



Crystallized ferberite 19 



Composition of ferberite and other members of the wolframite series 19 



Definition of ferberite and other members of the wolframite series 37 



The excess of ferrous oxide and manganous oxide 38 



CRYSTALLOGRAPHY OF FERBERITE FROM BOULDER COUNTY, COLO., by Walde- 



marT. Schaller 40 



Previous publications 40 



General characters of the crystals 40 



Mode of occurrence 40 



Size 41 



Color and cleavage 42 



The measured crystals by localities 42 



Axial elements 43 



Calculation of values 43 



Comparison of values 45 



Forms and angles 46 



New forms - 



Forms previously described 



Common forms 



Rare forms 



3 



