CONTENTS IX 



Hematite 59 



Carbonates 59 



Calcite 59 



Dolomite 59 



Malachite 59 



Smithsonite 60 



Cerussite 60 



Silicates 60 



Kaolin 60 



Sulfates 60 



Barite 60 



Occurrence of the Barite 62 



Veins 62 



Croppings 63 



Character of the veins 63 



Form and structure 63 



Relation to the wall rock 64 



Geological distribution 64 



Areal distribution 64 



Value 64 



Disseminated Barite 64 



Cave Deposits 65 



Residual Deposits of Barite 66 



Croppings 66 



Character of the residual deposits 67 



Form and structure 67 



Relationship to the other types 69 



Geological distribution 69 



Areal distribution 70 



Concentration of the Barite by Weathering 70 



The weathering 71 



Source of the barite 73 



Conclusion as to concentration by weathering. ... 75 



Origin of the Barite 75 



Concentration from the surrounding rocks 75 



Source of the barium 77 



Method of concentration 81 



Solubility of barium salts 81 



