» Fri Jun 08, 2012 10:19 pm
The larger the soul gem (with a soul inside it), the more damage the enchant will do, or the larger the magicka regeneration, etc.
So a black soul gem would be the highest - but I would save those for special weapons.
Also, let's say you use a great soul gem, and it takes one of those for the enchant, and gives you 30 charges before the enchant runs out.
When you "recharge" the weapon - put another soul gem in it - it would take one greater soul gem (one for one exchange). But if you didn't have a greater soul gem, you could use 2, 3, or 4 lower ranking soul gems to recharge the weapon to the same level of 30 charges.
Hope that makes sense and answers your question.
Good luck.