The Topaz Staff is the lowest tier of staff that can be crafted out of gems. It is the lowest strength magic weapon in the game. It only uses 3 mana and has a very cheap recipe. Its projectile can go through one target before dissipating.
The Topaz Staff is equivalent to the Amethyst Staff and is only available on worlds where Tin replaces Copper (although the player can still obtain all the ores via the Extractinator).
It can also be used as a light source, as there is a large flash, brightening up the whole area, when fired. This can help with cave exploration.