DEPARTMENT OF THE INTERIOR FRANKLIN K. LANE, Secretary UNITED STATES GEOLOGICAL SURVEY . GEORGE OTIS SMITH, Director Bulletin 610 MINERALOGIC NOTES SERIES 3 BY WALDEMAR T. SCHALLER WASHINGTON GOVERNMENT PRINTING OFFICE 1916 CONTENTS. Page. Introduction................................................................ 9 Koechlinite (bismuth molybdate), a new mineral............................ 10 Origin of investigation................................................... 10 Nomenclature......................................................... 10 Locality............................................................... 11 Paragenesis........................................................... 11 Crystallography........'............................................... 14 General character of crystals....................................... 14 Calculation of elements............................................. 14 Forms and angles................................................. 15 Combinations..................................................... 19 < Zonal relations and markings...................................... 19 Habits........................................................... 21 Twinning........................................................ 23 Measured crystals................................................. 26 Etch figures...................................................... 27o Intergrowths........................................................ 31 Relation to other minerals.......................................... 31 Physical properties.................................................... 32 Optical properties...................................................... 32 Chemical properties.................................................... 33 Pyrognostics...................................................... 33 Quantitative composition.......................................... 33 Diagnostic properties................................................... 34 Inyoite and meyerhofferite, two new calcium borates......................... 35 Relation of meyerhofferite to inyoite................................... 35 Nomenclature......................................................... 36 Locality and paragenesis.......................'....................... 36 Inyoite............................................................... 37 Crystallography................................................... 37 General character of crystals................................... 37 Calculation of elements......................................... 37 Forms......................................................... 38 Physical properties................................................ 38 Optical properties.................................................. 38 Chemical properties...............................................: 39 Pyrognostics.................................................. 39 Quantitative composition...................................... 39 Alteration.................................................... 40 Diagnostic properties............................................... 40 Meyerhofferite............... ......................................... 41 Crystallography................................................... 41 General character of crystals................................... 41 Calculation of elements......................................... 41 Forms and angles............................................. 45 3 4 . CONTENTS. Inyoite and meyerhofferite, two new calcium borates Continued. Meyerhofferite Continued. Crystallography Continued. Page. Combinations................................................. 48 Zonal relations................................................. 50 Habits....................................................... 50 Measured crystals............................................. 52 Physical properties................................................ 53 Optical properties.................................................. 54 Chemical properties................................................ 54 Pyrognostics.................................................. 54 Quantitative composition...................................... 54 Synthesis....................................................... 55 Diagnostic properties. v............................................ 55 Lucinite, a new mineral: a dimorphous form of variscite ..................... 56 Origin of investigation................................................. 56 Nomenclature and locality............................................. 56 Paragenesis........................................................... 56 Crystallography....................................................... 57 General character of crystals....................................... .57 Calculation of elements............................................. 58 Forms and angles................................................. 59 Combinations..................................................... 61 Zonal relations..................................................... 61 Habits........................................................... 61 Measured crystals................................................. 62 Relation to other minerals......................................... 64 Physical properties.................................................... 66 Optical properties...................................................... 67 Chemical properties.................................................... 67 Diagnostic properties.................................................. 68 The crystallography of variscite............................................. 69 Previous description.......................... i........................ 69 General character of crystals........................................... 69 Calculation of elements................................................. 69 Forms and angles.......:............................................. 71 Combinations......................................................... 73 Zonal relations......................................................... 73 Habits...... ; ........................................................ 73 Twinning.............................................................. 77 Relation to variscite crystals from Arkansas............................. 78 Schneebergite............................................................. 81 Origin of investigation................................................. 81 Historical sketch....................................................... 82 Bibliography......................................................... 85 Paragenesis........................................................... 86 Crystallography....................................................... 90 Physical properties.................................................... 91 Optical properties...................................................... 91 Chemical properties.................................................... 91 Pyrognostics...................................................... 91 Homogeneity of sample analyzed................................... 91 Analytical methods used........................................... 92 Quantitative composition. .......................................... 93 CONTENTS. Romeite........................... ..........................' .:............ 95 Origin of investigation................................................. 95 Historical sketch....................................................... 95 Bibliography......................................................... 96 Paragenesis........................................................... 96 Crystallography....................................................... 97 Physical properties.................................:.................. 98 Optical properties...................................................... 98 Chemical properties.................................................... 99 Pyrognostics...................................................... 99 Quantitative composition.......................................... 99 The natural antimonites and antimonates..........\......................... 104 Velardenite, a new member of the melilite group............................ 106 The melilite group........................................................ 109 Historical sketch..................................................... 1. 109 Review of old theories............................................. 109 Characteristics of the melilite group. ................................. 110 New theory............................................................ Ill Primary compounds................................................ Ill Natural anhydrous calcium-aluminum silicates.................. Ill Sarcolite...................................................... 113 Soda sarcolite.................................................. 115 JLkennanite.................................................. 116 Velardenite................................................... 117 Summary of properties of primary compounds................... 117 Isomorphous mixtures of two or more of the primary compounds...... 118 Composition of the mixtures........................................ 126 The composition of cebollite............................................... 129 The crystallography of thaumasite.......................................... 131 The chemical composition of tremolite...................................... 133 New occurrences of some rare minerals....................................