Crystal Tears - - are a special resource that can be obtained by completing the Maze. They are used to unlock unique upgrades for your dungeon. You can find these upgrades and see how many Crystal Tears you have in the dungeon upgrade menu. 
The more health you have when you reach the chest at the end of the Maze, the more Crystal Tears you will receive. For example, if you finish the maze with 3 stars, you will receive 15 Crystal Tears; if you finish with only 1 star, you will only receive 5 Crystal Tears.
Moreover, each time you reach the chest in the Maze, you have the chance to win additional rewards, such as orbs, gold, keys and more Crystal Tears using the spinner.