Dark Emerald

Dark Emerald is a special gem created by combining Perfect Emerald, Flawless Sapphire and Flawed Topaz .

It is single-target gem with the special effect of stunning units, 12.5% chance to stun for 1.5 seconds. It can be upgraded once to Enchanted Emerald for 250 gold. The upgraded mode has a 15% chance of stunning units for 2 seconds, and a 15% chance of doing x4 damage.

In survival mode, when keeping Enchanted Emeralds out of range of air troops, there is limited space to place them in down left corner:

Enchanted Emeralds placed entirely within green or cyan area will not hit bats. When hitting bats, they have 1,5* damage multiplier due doing green damage.