X BULLETIN J 2, UNITED .STATES NATIONAL MUSEUM. 



NOXMETALLIC ORES. Page. 



Sulphur:- 



Sulphur minerals 'iOl 



Sulphur 201 



Pyrite , 201 



Sphalerite 201 



Sulphur ores 201 



Application of snlpbur 201 



Manufacture of sulphuric acid 202 



Grinding and polishing materials 203 



Corundum 203 



Emery 203 



Quartz ' 204 



Tripoli -^ 204 



Pumice stone 205 



Garnet 205 



Manufacture of sandpaper 205 



Ashestos : 



Asbestos minerals 206 



Application of asbestos 208 



Phosphates : 



Phosphate mineral j 209 



Apatite 209 



Phosphate ores 209 



Apatites 210 



Phosphorites 211 



Rocli phosphates _ 211 



River phosphates 211 



Phosphatic limestone 212 



Gnauo 212 



Bone deposits 213 



Clays 213 



Carbon group : 



Pure carbon series 217 



Diamond 217 



Graphite 217 



Application of graphite 218' 



Coal series : 



Coal 219 



Anthracite 221 



Send-authracite 227 



Seiiii-bitnmiuous 228 



Bitununous 229 



Peat or turf 234 



Bitumen series 235 



Solid "bitumen 235 



Asphalt 235 



Albertite 236 



Uiatite 236 



Petroleum 236 



Specific gravity series 237 



Color series 239 



Geological series 240 



Geographical series 243 



Technology 251 



Natural gas , 255 



