14 



CONTENTS. 



Chapter V. — Minerals — Continued. Page. 

 Section 3. Rock-making minerals — Continued. 

 The silicates — Continued. 



Chlorite group 345 



Amesite, corundophilite, prochlorite, clinochlore, and penninite 345 



Occurrence 346 



Alterations 347 



Serpentine-talc group 348 



Serpentine and tale . 348 



Serpentine 349 



Occurrence 349 



Alterations 349 



Talc - 350 



Occurrence 350 



Alterations 351 



Glauconite 351 



Occurrence 351 



Alterations 351 



Kaolin group . . , - - 352 



Occurrence 352 



Alterations 352 



Summary of alteration of silicates 352 



The titanates - 354 



Titanite and perovskite 354 



Titanite 354 



Occurrence 354 



Alterations 355 



Perovskite 355 



Occurrence 355 



Alterations 355 



The phosphates 356 



Apatite - 356 



Occurrence . 356 



Alterations 356 



The sulphates - 357 



Anhydrite and gypsum 357 



Anhydrite 357 



Occurrence 357 



Alterations 357 



Gypsum - - - 357 



Occurrence 357 



Alterations 358 



Section 4. General statements 359 



Physical-chemical factors upon which nature of alterations depends 359 



Chemical composition 359 



