Play games
Choose the game that interests you and play itfor free.
Complete the quests
Every game has some quests for which you will receive Soul Gems.
Receive rewards
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
I hae been using this site for some time and I colected few gemstones, but I dont really want to use any of them because I mainly get my gems from appzone, is there any way to sell them or do anything else with them exept activating them?