UNITED STATES MINERAL RESOURCES 



LITHIUM, CESIUM, AND RUBIDIUM- 

 THE RARE ALKALI METALS 



By James J. Norton 



CONTENTS 



Abstract of conclusions 365 



Introduction 365 



Lithium 366 



Lithium deposits in pegmatites 367 



Geology 367 



Mineralogy 367 



Petrogenesis 368 



Crystallization of lithium-rich pegma- 

 tite 368 



Origin of pegmatitic magma 368 



Lithium pegmatite localities 369 



United States 369 



Canada 369 



South America 370 



Africa 370 



Eurasia 370 



Australia 370 



Lithium in brines 370 



Other lithium deposits 371 



Exploration and mining 371 



Reserves and resources 372 



Resources in pegmatites 372 



United States 372 



Canada 373 



Africa 373 



Eurasia, Australia, and South America. 374 



Resources in brines 374 



Summary of lithium reserves and resources. 375 



Cesium 375 



Geology 375 



Production 376 



Reserves and resources 376 



Rubidium 376 



Research suggested 377 



Selected references 377 



TABLES 



71. Crustal abundance of rare alkali metals 



72. Composition of lithium minerals mined from 



pegmatites 



73. Lithium resources 



Page 



366 



367 

 372 



ABSTRACT OF CONCLUSIONS 



Lithium, cesium, and rubidium, though rare in comparison 

 with sodium and potassium, are abundant relative to the ap- 

 parent commercial need for them. Lithium and cesium both 

 form independent minerals in pegmatites. Lithium produc- 

 tion from brines has increased so greatly in recent years 

 that it has taken much of the market away from pegmatitic 

 lithium. Rubidium forms no known independent minerals but 

 exists chiefly as a substitute for potassium, especially in 

 minerals formed late in the crystallization of pegmatites. 

 Most commercial rubidium and some cesium have been ob- 

 tained as byproducts of processing lepidolite. 



The world's proved and probable reserves of lithium, most 

 of which are in the United States, are 1,200,000 tons, or 

 about 400 times the 1970 consumption. Additional resources 

 in known lithium regions are about 10 million tons, and 

 even this large figure probably could be increased many 

 times by intensive search throughout the world. 



World cesium reserves are 100,000 tons, which also is 

 vastly greater than consumption and probably much less 

 than could be found if needed. For rubidium, meaningful 

 resource estimates cannot be made, but surely the supply ob- 

 tainable at current prices is plentiful. 



To prepare for new uses frequently proposed, especially 

 uses of lithium, knowledge of the geology of rocks and 

 waters that are enriched in rare alkalis should be increased. 



INTRODUCTION 



The alkali metals include, in addition to the abun- 

 dant elements sodium and potassium, four much 

 rarer members — lithium., cesium, rubidium, and 

 francium. Lithium, atomic number 3, has been mined 

 and used since the latter part of the 19th century, 

 and by the 1950's it had become the basis for an 

 industry of moderate size. Cesium and rubidium, 

 atomic numbers 55 and 37, respectively, have never 

 been used in quantities of more than a few thousand 

 pounds per year, virtually all of which is a byproduct 

 from lithium mining. Cesium in the mineral pollu- 

 cite does occur in deposits that would be minable 

 for cesium alone if the market were larger, though 

 even in these deposits cesium is a byproduct in the 

 sense that it is generally found during exploration 



U.S. GEOL. SURVEY PROF. PAPER 820 



365 



