Another set of materia questions

[Viladin]

I have a few questions in regards to how materia gains experience and how it confers benefits to a character:

1. The rules state that a piece of materia takes 10 percent of experience earned as its own. Does this mean that this is in addition to experience normally gained, or does it actually take away experience gained by the character in order for these materia to grow in level?

2. In order for materia to give its benefits to a character, it must be equipped into an item. However, what does that say for the item itself? Must it be actively worn/wielded in order to give its benefits? I can definitely see this being the case for additional damage dice from elemental materia on a weapon, but the mechanic seems a bit vague, and potentially clunky/awkward, if a character begins to draw different weapons/shields in combat that are equipped with passive benefit materia, like Ability Boost and Endurance Materia. Can a materia-equipped weapon merely be carried on a character to yield its benefit and gain experience?

Thanks for any clarification!

1. In addition to experience normally gained.

2. Has to be equipped to gain any benefits as well as gaining MXP.