DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, DIRECTOR BULLETIN 509 MINERALOGICAL NOTES SEKIES 2 BY WALDEMAR T. SCHALLER WASHINGTON GOVERNMENT PRINTING OFFICE 1912 CONTENTS. Page. Introduction............................................................ 7 A study of the rutile group............................................... 9 Introduction........................................................ 9 Characteristics of the rutile group...................................... 9 Primary compounds.................................................. 10 Chief primary compounds........................................ 10 Minor primary compounds.....,................'.................. 12 Isomorphous relations of primary compounds.....:.................... 13 Isomorphous mixtures of essentially two of the primary compounds....... 15 Ferrous columbate and ferrous tantalate............................ 15 Ferrous tantalate and stannyl stannate. ............................ 18 Stannyl stannate and titanyl titanate .............................. 22 Titanyl titanate and ferrous titanate............................... 22 Titanyl titanate and titanyl vanadate............................. 26 Stannyl stannate and ferrous stannate.............................. 27 Isomorphous mixture of more than two of the primary compounds....... 29 Striiverite........................................................ 29 Ilmenorutile..................................................... 33 Arsenical cassiterite.............................................. 36 Conclusion.......................................................... 37 Barbierite, monoclinic soda feldspar........................................ 40 Crystallized turquoise from Virginia. ...................................... 42. Introduction........................................................ 42 General description................................................... 42 Crystallography...............................'........................ 43 Chemical composition................................................. 44 Summary............................................................ 47 Crystallized variscite from Utah.......................................... 48 Introduction........................................................ 48 Occurrence and gem quality.......................................... 48 General description!.................................................. 50 Optical properties.................................................... 50 Orientation and pleochroism...................................... 50 Refractive indices................................................ 51 Structure of crystals..................................."........... 52 Properties of dehydrated lavender variscite......................... 53 Relation to analogous minerals................................... 55 Crystallography....................................................... 57 Introduction.................................................... 57 Calculation of elements........................................... 58 First orientation.................................................. 60 Second orientation................................................ 61 Third orientation................................................ 62 Twin crystal..................................................... 62 Relation to analogous minerals.................................... 62 3 4 CONTENTS. Crystallized variscite from Utah Continued. Page. Chemical composition................................................. 63 General properties............................................... 63 Chemical analysis................................"................. 64 Hinsdalite from Colorado .................................................. 66 Introduction........................................................ 66 Occurrence.......................................................... 66 Description of mineral............................................... 66 Chemical composition.................................................. 67 The alunite-beudantite group............................................. 70 Introduction......................................................... 70 Probable identity of hamlinite with goyazite........................... 70 Utahite and related minerals......................................... 71 Miscellaneous notes................................................... 74 Classification of minerals of the group................................. 75 Some minerals from Beaver County, Utah................................. 77 Introduction........................................................ 77 Beaverite............................................................ 77 Occurrence and association........................................ 77 Physical properties.............................................. 78 Chemical composition..........................'................... 78 Wurtzite...........'.................................................. 79 Occurrence...................... '. ............................... 79 Crystallography................................................... 80 Plumbojarosite....................................................... 80 Occurrence and physical properties................................ 80 Chemical composition............................................. 81 Corkite.............................................................. 82 Occurrence and physical properties................................ 82 Chemical composition................'............................. 82 Ferritungstite from Washington........................................... 83 Notes on minerals from gabbro, of Waimea Canyon, Hawaii.................. 85 Introduction........................................................ 85 Apatite.............................................................. 85 Orthoclase........................................................... 86 Titaniferous augite............................ r ...................... 86 Cuprodescloizite from California.......................................... 88 Mineralogy of the .French phosphorites..................................... 89 Introduction. ......................................:.... :............ 89 Types of phosphorites. ............................................... 89 Description of minerals................................................ 90 Dahllite.......................................................... 90 Francolite1....................................................... 91 Unknown mineral............................................... 91 Collophanite..................................................... 91 Quercyite........................................................ 92 Summary of properties................................................ 92 Chemical composition.................................................. 94 The probable identity of podolite with dahllite............................. 96 The composition of the phosphorite minerals............................... 98 Introduction........................................................ 98 Dahllite............................................................... 98 Francolite........................................................... 98 Collophanite......................................................... 99 Summary............................................................ 100 CONTENTS. 5 Page. Natramblygonite from Colorado........................................... 101 Occurrence.......................................................... 101 Association............................................ v.............. 101 Description of mineral............................................... 101 Chemical composition................................................. 102 The properties of mosesite................................................ 104 General description................................................... 104 Chemical properties.................................................. 104 Crystallography....... '. ............................................... 106 Optical properties.................................................... 107 Thaumasite from Beaver County, Utah..................................... 110 Introduction........................................................ 110 Geologic occurrence.................................................. 110 Physical character.................................................... Ill Chemical composition................................................. 112 Bibliography......................................................... 113 The identity of stelznerite with antlerite................................... 114 ILLUSTRATIONS. Page. PLATE I. A, Crystallized turquoise; B, Variscite nodule; C, Variscite crystals. 42 FIGURE 1. Structural formulas for chief primary compounds of the rutile group. 14 2. Turquoise crystal............................................... 44 3. Variscite crystal, showing grouping of small particles. ............ 53 4. Variscite crystal............................................... 58 5. Wurtzite crystal............................................... 80 MINERALOGICAL NOTES, SERIES 2. By WALDEMAR T. SCHALLER. INTRODUCTION. The several papers here assembled represent in part the results of mineralogical research work carried out by the author in the chem­ ical laboratory of the United States Geological Survey from January 1, 1910, to the end of the fiscal year 1910-11 (June 30, 1911). Ear­ lier reports of a similar