Enchanting and gem removal

Does anyone know if you have all gems slotted and THEN enchant the weapon. Will it remove all gems from weapon? Or still keep the first gem slotted?

Better late than never, but you will lose the lost slots for gems (slots 2,3,4) but keep slot 1. same with rune slots 3 and 4 they are lost. It is a much better practice to enchant before slotting to make sure you like the rolls first. Ive heard some rumor that tbe lost gems influence the enchants but i have seen nothing of the sort on my testing or heard any validation on this. (My testing was trying to get exp gain on a stsrter shortsword, not extensive, but for reference of how i tested) and one of the best parts of this game is that white gear is great gem it up!

You keep the first gem but the gem range will reroll and it can go lower than what you have.
I would enchant first then add gem.

Also I notice some gems give higher bonuses if the item is enchanted but not all.