During Sundays there will be a PVP Event which gives a different color of PVP Gems (randomized? Hero fragments are on the store).
-You will be given a purple/epic PVP gem upon winning similar to the normal PVP.
-You can use it to buy from an Epic Sunday PVP Store
-Purple/epic PVP gems will only last for the entire day of Sunday and will vanish after. (so people can’t hoard it.)
Since it only comes once a week people will be reviving their character multiple times just to get those fragments. (more money for you developers)
Knowing that this special PVP Gems will last only a day, people will use their gold to get a certain margin like 1000 Purple/Epic PVP Fragment. (Again more chances of getting money)