Exploring Earth Science - an absolutely excellent series of videos by Mike Sammartano on geological topics including rock and mineral identification, geological processes, landforms . . . it's all there. You can subscribe or watch for free.
Ore deposits 101Andrew Jackson, 11 units on different types of ore deposit, a bit slow in places but plenty of useful information on deposit origins
Earth optics videos - a series of 7 videos providing an excellent explanation of microscopy for geologists
Gold, faults and fluids - a video with Clive Willman and Rick Sibson: nice clear descriptions of faulting and subsequent metamorphism.