IV TABLE OF CONTENTS 



Descriptions of minerals — Continued. Page 



Gersdorffite 134 



Arsenopyrite 136 



Danaite 143 



Marcasite 145 



Sylvanite 145 



Kermesite 146 



Chalcostibite 147 



Galenobismutite 147 



Miargyrite 148 



Dufrenoysite 150 



Aikinite 151 



Boulangerite 151 



Pyrargy rite 155 



Proustite 158 



Pyrostilpnite 160 



Xanthoconite 160 



Owyheeite 160 



Jamesonite 162 



Tetrahedrite 163 



Tennantite 168 



Stephanite 168 



Polybasite 1 69 



Pearceite 171 



Enargite 171 



Halite 172 



Cerargyrite 172 



Embolite 174 



Bromy rite 175 



Iodyrite 175 



Fluorite 175 



Lawrencite 176 



Quartz 177 



a. Common quartz 177 



b. Rock crystal 177 



c. Amethyst 178 



d. Pseudomorphous quartz 179 



e. Chalcedony 180 



/. Jasper 181 



Tridymite 182 



Opal 182 



Valentinite 187 



Molybdite 187 



Tungstite 188 



Cervantite 188 



Stibiconite 189 



Cuprite 189 



Tenorite 1 92 



Corundum 193 



Hematite 194 



Ilmenite 197 



Spinel 198 



Magnetite 198 



Minium _. 199 



