no there is no where to buy them they are caves only. but there natural things in caves,
so no on ownes them so ur not steelin

ps you can get a giant skull in a cave with vampires.

actually you CAN buy them , if not from the mages guild then certainly from the dark
brotherhood. Be4 the purification the khajiit in the sanctuary will SOMETIMES sell them ,
once the purification is done then another person , this time a female imperial , will
start selling the same stuff.

mostly you will find them in caves and such , but you can always go to the sancutary once
every 3 days to check if they have some to sell.

whenever i start a new character immadately i go to chorrol mages guild sign up and in the
right back corner in the very first room is a case it contains 1 empty grand and 4 empty
commmon soul gems. btw you can dupe the soul gems with the light blue icon in your bag
thats what i do so go look up a dupe for whatever downloaded version u are using (if any).

you can buy them from earandil of whatever his name is in the mystic emporium and EVERY
alchemist in mages guilds

Hes right

you can get them at the mages guild if you join them some of them you can take without
stealling