For 30 contiguous days, The Etherian Gem Miners will deliver 100 gems once per day when you login to Dungeon Defenders II.

Upon loading into the town or a map, you will receive a notification of your delivery of gems for that 24 hour period.

Remember that you have to log in daily to claim your rewards and reap the maximum value! If you remember to log in every day, you'll end up with 3000 gems total!