Dimitra's violin and bow are made of enchanted wood, stained with a dark oil that gives the violin a black coloring. Within the oil was an anti-magic spell that coats both the inside and outside of the instrument, protecting it from harm.
The violin, when played within a certain range of notes seperated by each of the four strings, can tap into one of the four elements of the world. Earth; ranges from the lowest note on the violin, the open G, to low C on the G string. Water; ranges from the open D, to open A. Fire overlaps with water due to Dimitra's natural ability to weild fire, allowing her to tap into both at the same time if she chooses. Fire; ranges from open A to D, different from water's open D (an octave higher). And Air; ranges from open E to as high as she is able to play (C8 with harmonics).
She is able to weild fire and a single, other element when playing the violin due to her natural abilities. Dimitra cannot summon more than one element at a time with her violin, she must "end" her song for the current element before summoning another.
The violin is soul bound to Dimitra, if her soul is lost or moves on from the current plane of existence, the violin will follow. Nothing can break this bond.