I am past MR 50 as of now and haven't found any materials needed for augmenting my equipment (weapon and armor). I did a few tempered monster hunts (threat level 1) as well as some "Guided Lands".

So the question arose as to where to find/get the materials. They mostly look like stream stones, but are not limited to them.

To be a bit more specific, I want to add augment slot to my weapon and extend the upgrade limit of my armor. I would like to know where I can get the needed materials for these upgrades.