You can use unique gems and emeralds in order to learn spells in the ancient totem.

Each spell is useful to thieves. There are two types of spells - temporary and permanent. Temporary spells can be learned once, and they will work for a certain amount of time. When the time is up, you can buy another temporary spell. The effect of a permanent spell will not disappear and will increase as you upgrade it.

Tap on the exclamation mark next to the spell's name and you'll be able to read the spell's description: what type it is (permanent or temporary) and the maximum level for permanent spells.

You will receive extra experience points when you learn new spells or upgrade existing spells.

Temporary spells:

1. Unstoppable thief: let you skip a dungeon for free when attacking other players.

2. Proficient thief: gives an extra chance to steal a gem from other player.

3. Skilled defender: gives an extra chance to defend your gem from other players' attacks.
 
4. Rescuer: gives an extra chance to retrieve gems automatically.
 
5. Universal Gem Wizard: increases the rating of the gems given in rituals and stolen from raids.
 
6. Yellow Gem Wizard:  increases the rating of the yellow gems given in rituals and stolen from raids. 
 
7. Red Gem Wizard:  increases the rating of the red gems given in rituals and stolen from raids. 
 
8. Purple Gem Wizard:  increases the rating of the purple gems given in rituals and stolen from raids.  
 
9. Green Gem Wizard:  increases the rating of the green gems given in rituals and stolen from raids.   
 
10. Blue Gem Wizard: increases the rating of the blue gems given in rituals and stolen from raids.   

Permanent spells:

1. Trap engineer: decreases trap upgrade time.

2. Generous totem: gives an extra chance to get bonus magic item.

3. Seeker: gives additional tears in the maze chest.

4. Totem revival: gives a chance to restore a broken totem for free.

5. Wise builder: decreases skill upgrade time.

6. Best friend: gives an extra chance to retrieve a gem to your friends or guildmates.

7. Justice: gives an extra chance to retrieve your own gem.
 
8. Precious treasure: when you save a gen in the Treasure Hall, it gives you a chance the rating of your saved gem will be increased.
 
9. Insatiable: gives an extra chance to add more bonus rating to stolen gems.
 
10. Lucky Thief: gives an extra chance to find an additional reward after attacking other players.
 
11. Quickie: gives an extra chance to save your trap layout in just one try.
 
12. Potion Thief: gives an extra chance to recover the used potion after a successful raid attempt.
 
13. Greedy Thief: increases your maximum gold capacity.
 
14. Master Miner: gives a chance to increase the value of gems collected in mines.