The Scrying orb is an item used in the Enter the Abyss miniquest, given by the mage located in the south-east section of Varrock, in the Zamorak church. This item has a one time use for the sole purpose of this mini-quest and is henceforth never used.
The scrying orb needs to be filled with magic energy by teleporting to the Rune essence mine. Having the orb in the player's inventory while being teleported to the rune essence mine will partially fill it, while teleporting from 3 different locations to the rune essence mine will fill the orb entirely. Once players give the orb back to the mage, they never use the orb again.