58:34

Physical properties of minerals

27:44

Optical Mineralogy Pt.1- Plane & Cross Polarized Light, Birefringence, Pleochroism, etc. | GEO GIRL

28:32

Interference figures

27:03

Optical properties of biaxial minerals

1:19:11

FINGERPRINT CLASSIFICATION- CLASSIFICATION FORMULA

23:47

Metamorphism of pelitic rocks

19:17

Rock and Mineral Identification

1:10:19

EARTH 4K - Relaxation Film - Peaceful Relaxing Music - Nature 4k Video UltraHD - OUR PLANET