CONTENTS. 13 



Chapter V. — Minerals — Continued. Page. 

 Section 3. Rock-making minerals — Continued. 

 The silicates — Continued. 



Epidote group 320 



Zoisite, epidote, piedmontite, and allanite 320 



Occurrence 320 



Alterations - 322 



Axinite - 323 



Occurrence 323 



Alterations 324 



Prehnite - 32-1 



Occurrence - 324 



Alterations 324 



Humite group 325 



Chondrodite, humite, and clinohumite 325 



Occurrence 325 



Alterations 325 



Tourmaline 326 



Occurrence - 326 



Alterations 326 



Staurolite 327 



Occurrence 327 



Alterations 327 



Zeolite group 329 



Thomsonite, hydronepbelite, natrolite, mesolite, scolecite, analcite, apophyl- 

 lite, epistilbite, heulandite, stilbite, phillipsite, harmotome, gismondite, 



chabazite, gmelinite, and laumontite 329 



Occurrence 331 



Alterations - - 333 



Mica group 336 



Muscovite, paragonite, biotite, and phlogopite 336 



Muscovite - - . 336 



Occurrence — 336 



Alterations — 337 



Paragonite - - - - 338 



Occurrence - - - 338 



Alterations . . _ - 338 



Biotite 339 



Occurrence 339 



Alterations - - 339 



Phlogopite - - - 343 



Occurrence — - 343 



Alterations 343 



Clintonite group 344 



Margarite, chloritoid, and ottrelite 344 



Occurrence 344 



Alterations 345 



