Teleporter gem => if you click on the teleporter, a dialogue should pop up => insert gem or leave.

Please, check which ranking quests are still available in your case => you need about 10000 ranking XP to beat Serrick on the ranking list. And max is 25000. Ranking XP count from the time on, when you're added to the list the Keeper of Ranks makes.

Stolen goods 1500
Talking Tibar 2500
Lost relic 2500
Ball in well 500
Book for Barnabus 2500
Book for witch 2500
Man turning into crystal/cure for... 1500+1500
Kill an assassin 1500
kill Fire Elemental 500
Zandalor wants an artifact 500
Missing monks 2500
Strange teleportations 5000