The enchanted gem is an item used in the Slayer skill. They are sold by all Slayer Masters for one coin. These allow a player to contact the slayer master that has assigned them their current slayer assignment, where they can ask for tips, ask who the master is and where they are located, and check how many monsters they still have left to kill for their slayer assignment. However, it will not allow players to ask Slayer masters for new Slayer tasks.
The player can craft these enchanted gems into slayer rings at level 75 Crafting, provided they have unlocked the ability to do so, which can be purchased for 300 slayer points at any Slayer Master. In order to craft a slayer ring you need to use a gold bar on a furnace with a ring mould and enchanted gem in your inventory. The gem is also used to craft a Slayer helmet, along with other items, after purchasing the ability to do so for 400 slayer points.
An alternative to the gem is a charged Combat bracelet, which will update the player after every 10 kills when equipped.
The Enchanted gem is a component of the Commorb obtained from Sir Tiffy Cashien during the Wanted! quest., As of 12 December 2013, the enchanted gem has a right-click option to bring up a log recording every Slayer monster the player kills. Once a player reaches 65,535 kills the log will say “Lots!” for that particular monster.