what is the difference? Both are unbreakable and reusable or only one is?

azures is unbreakable and reusable but dont know about the other

The Black Star is also unbreakable, can hold Black Souls (human souls) and according to the quest-giver can only hold black souls. Of course, I've found it to hold white souls just fine...

Black star is for humanoid souls only, which are always grand souls. Azuras star is for creatures' souls only, of which only mammoths are grand I believe.

It's basically an RP decision. Collecting black souls is considered somewhat of a .... heinous crime, but having the black star makes it easier for you to collect souls in general.

Black star supposedly only holds black souls (human souls) but I have capture animal souls in it. Azuras star cannot capture human souls though. both are unbreakable and reusable

Wait, seriously? I screwed up big time then!

I can almost guarantee that the Black Star is going to get patched. I chose the normal star for that reason.

Higher level animals and creatures like trolls and higher level falmer and dremora are grand, too. Also, when getting Azura's Star, you can also get her disciple to be a follower.

i don't understand the difference in grand and non grand gems. I know how to enchant items, disenchant items but do not know the difference in petty / grand / black / white soul gems. What is the difference?? other than price of course.

The mage companion is pretty solid too.
Lydia died on me while delving Alfthand, but Illith(?) mostly keeps her mouth shut and casts what seems like endless ice bolts and lightning blasts. If only I could get her to consistantly wear the gear I give her. Even when loading out with better base gear, she only puts it on sometimes, rarely in combat but almost always in towns.

Level of magic/strength of enchantment/number of charges. PettyPetty, Lesser, Common, Greater, and Grand are white souls gathered from creatures and animals. The strength and level of the animal determine the level. Also, a Grand soul gem can hold Grand souls and all lower-level souls, but a smaller soul gem cannot hold any higher-level soul.
Black soul gems hold souls gained from humans, and the soul's level is always Grand, no matter the strength/level of human.

The bigger the size / higher value the soul gem, the more CHARGES it'll give a weapon. Enchanting armor with a more powerful soul gem will make the enchantment stronger - for weapons it'll just give more charges.

Recharging a weapon with a soul gem, gives less charges back with weaker soul gems.

Black soul gems can be used in the exact same way as white soul gems, to enchant gear or recharge an item. The difference is the black soul gem holds a 'black' soul, which only comes from a sentient being. Harvesting black souls is strongly frowned upon by everyone in the game world. It demonstrates a strong ambition for power, even to the point of committing murder.

Oh okay thanks just read both posts.... that clears up everything thanks a lot

Depends on whether you're enchanting armor or weapons. But when in doubt, go bigger.

i was under the impression that putting points in enchanting tree made the enchants stronger. so to get the max enchantment i need to put points in enchanting tree + use the best soul gem around.

EDIT: Do armors need to be recharged?

thats true, but i use azuras star, either is workable, i buy grand souls for my major enchantments, but for just keeping weapons charged, azuras star works great for that, the black star is prob better if you want more grand souls all the time if you're gonna be enchanting lots of things it will save you some gold.