What AVID Is: an acronym that stands for Advancement Via Individual Determination an in-school academic support program for grades 4 â 12 that prepares students for college eligibility and success; for all students, but it targets those in the academic middle; implemented school-wide and district-wide; What AVID Is Not:
It's an item specific to Solstheim. Like Michael said, you can kill the big floating Netches. They're relatively slow, but hit hard if they get close. Arrows from range aught to do the trick if you've got a decent Archery score or relative magical ability. You can also buy them from the merchants on Raven Rock. Other than that, random loot is the only way to get it, but Netch Leather won't appear in Skyrim proper, it's only going to appear on Solstheim.
Skyrim: Finding Quicksilver Ore to make Quicksilver Ingots. There are many locations around skyrim were you can find quicksilver ore. However, there is one particular mine that is full of quicksilver ore veins. It is located in Dawnstar next to the northern most building on Dawnstar: