res 173

MANGANESE ORES 173
Economic features 173
Geologic features 176

CHROME (OR CHROMITE) ORES 178
Economic features 178
Geologic features 179

NICKEL ORES 180
Economic features 180
Geologic features 181

TUNGSTEN (WOLFRAM) ORES 182
Economic features 182
Geologic features 184

MOLYBDENUM ORES 185
Economic features 185
Geologic features 186

VANADIUM ORES 187
Economic features 187
Geologic features 188

ZIRCONIUM ORES 189
Economic features 189
Geologic features 189

TITANIUM ORES 190
Economic features 190
Geologic features 190

MAGNESITE 191
Economic features 191
Geologic features 192

FLUORSPAR 193
Economic features 193
Geologic features 194

SILICA 195
Economic features 195
Geologic features 196

CHAPTER X. COPPER, LEAD AND ZINC MINERALS 197