UNITED STATES MINERAL RESOURCES 



ARSENIC 



By J. L. GUALTIERI 



CONTENTS 



Abstract of conclusions 



Introduction 



Exploitation 



Geologic environment 



Geochemistry 



Minerals 



Types of deposits 



Enargite-bearing copper-zinc-lead deposits _ 



Arsenical pyritic copper deposits 



Native silver and nickel-cobalt arsenide de- 

 posits 



Arsenical gold deposits 



Arsenic sulfide and arsenic sulfide gold deposits 



Arsenical tin deposits 



Other deposits 



Resources 



Identified and hypothetical resources 



Speculative resources 



Prospecting techniques 



Problems for research 



Selected references 



TABLES 



9. World identified and hypothetical resources of 



arsenic 



10. Types of arsenic deposits of the vi^orld 



ABSTRACT OF CONCLUSIONS 



I 



Arsenic is used mostly in agriculture, where it is employed 

 as an insecticide, pesticide, and herbicide. It has limited use 

 in industry as an alloying agent and a chemical reagent. 



Current domestic consumption of arsenic is about 20,000- 

 30,000 short tons per year, but domestic production fills only 

 about a tenth of this. The rest is mostly supplied by other 

 countries of the free world, chiefly Sweden, France, and 

 Mexico. 



Arsenic is produced as a byproduct and occurs in several 

 types of deposits: enargite-bearing copper-zinc-lead deposits, 

 arsenical pyritic copper deposits, native silver and nickel- 



cobalt arsenide deposits, arsenical gold deposits, arsenic sul- 

 fide and arsenic sulfide gold deposits, and arsenical tin de- 

 posits. 



U.S. and world identified resources of arsenic are herein 

 estimated to be 1,300,000 short tons and 17,600,000 short 

 tons, respectively; these resources are more than sufficient 

 to fill projected needs until the year 2000. Hypothetical re- 

 sources for the United States and the world are estimated 

 at 650,000 short tons and 14,300,000 short tons, respectively. 



Speculative resources of arsenic are estimated to be 10 

 million short tons. Arsenic may be obtainable from organic 

 shale of marine origin; where such shale is subjected to 

 tectonic and metamorphic processes, contained metals may 

 migrate to and concentrate in favorable structures. 



INTRODUCTION 



Elemental arsenic in its most stable form is a 

 silver-gray metalloid, moderately hard but brittle 

 and having a specific gravity of about 5.73. It rarely 

 occurs naturally in its native state. 



Arsenic is chemically allied to a group of elements 

 vi^hich includes nitrogen, phosphorus, antimony, and 

 bismuth ; but it is physically more like antimony and 

 bismuth, vi^hich also have metallike qualities. 



Arsenic is important because of its toxic effect on 

 living matter; its principal use is in agriculture 

 where arsenic compounds function as insecticides, 

 pesticides, and herbicides. Arsenic acid is used as 

 a defoliant or dessicator to facilitate the mechanical 

 harvesting of cotton. Organic arsenic compounds are 

 used to control or to kill undesirable grasses and as 

 parasite control agents in poultry and livestock. 

 Other arsenic compounds are used as vi^ood preser- 

 vatives. 



Uses of arsenic in industry are minor compared 

 with those in agriculture. Arsenic is used as a de- 

 colorizer in the manufacture of glass, and arsenic 

 compounds are used as pigments in some enamels 

 and as reagents in flotation processes for separat- 

 ing minerals. 



Metallurgically, arsenic is used as a hardener for 

 lead in bearing metal, battery plates, and shot. It is 



U.S. GEOL. SURVEY PROF. PAPER 820 



51 



