Just a little oversized like 18" for higher visibility
At that length, you could use it even for officiating, for handfastings, or for an official fun talking stick at fae tea
I'd likely put something more sparkling(prism, facets glass,antique chandelier point) than a regular quartz crystal, although that'd be pretty too :)
and then I'd sculpt about a 1/3 of the handle with tree texture, shelf shrooms, vines, leaves, florals.
I"d do all of that on a natural piece of wood, something i found, which I have vases and vases full of.
I'd leave the wood itself natural, maybe rub some oil or beeswax mix into the wood a bit for color, sealing, preservation.