Dell

Dell (female) is one of the seven Diamond Kids. She has the grey diamond which allows her to use magic, from a magic staff. To use a spell, she can just say the key word of said spell, and the staff will execute the spell, but the spell must first be installed into the staff, which takes around ½-1 hour. When spells are executed, the key word is a normally unrecognisable phrase, but is actually old Diamondian, which dates back to 500+ years ago! This makes the spells that she casts extremely powerful, as they come from long ago.

Q&A
Q = Why does Dell have gray hair, if she's supposed to be about 10 years old?

A = Dell does not have enough pigment (the stuff that colors hair) in her hair, therefore making it gray. It is not due to age.

Q = Can other people use Dell's staff?

A = Kinda. The magic Dell uses to power her staff is stored in her diamond, which the other Diamonds have in their diamonds, but not nearly as much as Dell does. So yes, theoretically, if another Diamond were to use Dell's staff, they could use it, but only about one spell per day, because of the lack of magic compared to Dell.