When I began my doctoral research I was lacking a really good knowledge of clay rocks and clay minerals. So, during the years I have been looking for easy to understand resources on clay minerals and methods. Oddly enough I found the most useful resources now that I am closing in on finishing my project!
Anyways, I decided to share the best online resources. The first I found only last week. It is the YouTube channel of the Virtual Soil Science Learning Resources group initiated by Dr. Maja Krzic (UBC) in 2004. Their channel hosts dozens of short videos by soil experts on anything a starter might look for. I especially found the videos about methods, e.g. determining cation exchange capacity or salinity, the most useful.