Elder Scrolls 4: Oblivion Message Board  

Where can i find soul gems? I know that soul gems can be found from caves and something like that, but does anyone sell them?

The mages guild sells them and you can't buy black soul gems, but you can make them from grand soul gems.

Often you can find many of them lying around the arcane university.

they sell them in every town ?

and how can i make black soul gems from grand soul gems ?

well, first you need to find one of those alters (if you'be done the mage's guild quests, you know what i'm talking about, they have the death look to them, they're outside certain caves and forts, one of them is i think south of kvatch)

then, on a day where a purple-pink light is shining down on the alter, put however many gems you want into it, i.e. you wnat 5 black soul gems=you puting in 5 grand soul gems

then, cast a soul trap spell on the alter for how many gems are in it, then attack it with your weapon (it might be cast the spell once and attack it for how many gems are in it, try both ways)

then open the alter and there are your new hand-made black soul gems, you can capture people's souls in them

On this Link you'll find more info.