Sections of Granite and Basalt seen under polarised, light. 

 ( af ter 'Fouque 8c L e'vy) 



(D Quartz (2) Orthod.ase.f3) Oligoclase (4) Apatite (5jBiotite 



(6) Actmr 'vpidote. 



(8) Olivine (9) Labradorite . flO)Augite (Black) Magnetite 



