The key points in optical mineralogy

[@theendofmyropemydude]

Thanks, Kuwait geology club!

[@sunrajkarthi857]

Thanks for sharing it!!!

[@gemineseproduction]

This really helped out a lot. Thanks!

[@Zincman-2021]

on 1.30 I think the right picture has to switch N1 and N2. If use N1>N2, N1 has to above and N2 has to under. Sorry, if i misunderstand.

[@MitsuiSalgadoSaitoct]

:D!!!!!!!!!!!!