its been a long time since ive played the game but ill try to answer as good as i can magical items has have the amount of available magical power in terms of percentage so if the magical item says it adds 10 magical damage but if the amount of available magical power says 60% so you'll be only getting 6 magical damage.... hope that helps
...Also it has so much mana in a weapon. That mana, if you are magickal, and the object is identified, it will let you use some magickal spells so many times... After the mana is gone, I think it is gone for good.
Mana and spell charges are two different things. Spell charges are on several staves -- when you equip a charged item, the button to the left of the hotkeys becomes clickable. Click it to show the available spells. A number will also show up at the bottom of the screen, signifying how many times you can cast the item's spells. For example, the Staff of Healing lets you use Major Healing 20 times, after which it becomes fairly useless. The spell charges do NOT regenerate. Mana is on items such as Mage's Dagger, Mage's Staff, and most Arcane weapons. The mana basically acts as extra fatigue, and shows up in the gold/ammo counter when equipped. For example, the Arcane Great Sword has 20 mana. If you used a 50 cost spell, it'd use up the 20 mana in the Sword, and 30 of your own fatigue. Item Mana DOES regenerate. The regeneration is equivalent to a heal rate of 1 (I believe); waiting/sleeping an hour will fully recharge the item. Hope that helps. -Poiuyt Man
Item mana only acts as fatigue in respect to spells, however. Fatigue damage and so forth don't affect and aren't affected by item mana. Resting an hour doesn't always regenerate all mana. The Arcane Staff takes longer in my experience.