Songwood

The three most valuable things in the world by weight are songwood, dragon bones, and phase-spider silk in that order.

— Jasper Cameron, Leader of The Bronze Ravens.

There is something to be said for function over form. Many have tried to make a violin or lute out of precious metals decorated with gems, valuable enough to purchace one's own small kingdom, or a decent title in a larger one. All of them have sounded like shit. At least the guilded staff of an archmage has some use, although each archmage I have met would give that staff up in a second for one made of genuine songwood.
In color songwood is as pale as the moon, and has a similar glow to it if viewed in the dark. While relatively light in weight it boasts incredible strength. It is resistant to all but the most persistent of magical flames or the hottest of natural fires.
As a matter of fact, the two dwarven forges that have managed to burn a piece are celebrated by both dwarves and elves, although the elves may celebrate the exceptional magical items that those forges produce and not be aware quite where the exceptional magic comes from. You know, dwarves and their secrets.
How rare is songwood exactly? Well, there are 83 verified items made from it in the world. The elves of Feywillow have a song about the history of each one. While I wont list them all here, there are indeed 2 wizards staffs, as well as a shillelagh, a gladius, one harp, five lyres, the worlds first spyglass, the Crown of Feywillow, and several shields.
The name comes, of course, from the tune one hears when touching a piece of songwood. When wearing or holding a piece of songwood one can experience what has been described by Frejya Stormsong as "the most beautiful symphony ever dreamed." In fact the way one verifies songwood requires two separate pieces and people musically inclined enough to hum, play, or transpose what they are playing. You see while there are thought to be repeating themes, potentially linked to the pieces of songwood themselves, in the four centuries or so that the elves have been attempting to transpose the tune, no two bars are exactly the same. Think on that. A melody may repeat, but with a different harmony, or in a different key, or with a slight variation. Some druidsclaim that the song heard is the Voice of the World, but whether they are right or not, who can say?