This is a special gauntlet worn by Ishidate on his right hand and possessing two stone-based abilities.
The gauntlet's first ability is petrifying anything that it touches. When the target is touched, the eye on the gauntlet will open and send chemicals through their body, turning the body into stone; the amount petrified is dependent on how long the wielder touches the target. If treated with the appropriate medical ninjutsu, the petrified portion can return to normal. If the body remains in this stone form for too long, however, it will remain petrified forever. Also, the petrified part of the body will become brittle and fragile, making it easy to shatter and kill the victim.
The gauntlet's second ability is to manipulate stone in a telekinetic manner. Ishidate has used it to uproot chunks of stone from the rooftop, hover stone to use as a platform to stand on in mid-air, and break stones down to form numerous sharp, small stones to use to rain down on their target.