Jar is a Legends of Idleon item: quest reward.

Jar | Idleon Toolbox

Hold down to gain EXP in the skill that's displayed in the corner of your screen. If you're in a town, you will gain EXP in the town skill. The amount of EXP you get is based on your skill's Lv.

Medium_Experience_Balloon

Hold down to add these gems to your account. You can then spend them in the Gem Shop!

Wait, why do they want to pretend to have eaten you again? Uh oh, I don't like the look of that Quest Helper...