Same Issue
Region: US East
Server: Brazir
Character: ZedZulZorra
Same Issue
Region: US East
Server: Brazir
Character: ZedZulZorra
Same issue 
server: formax
user: rexotroy
Anyone’s get fixed by logging out for a while?
Hello
Same issue… it’s a “Know Issue” for the assistance.
We have to wait for a fix
Server: Lyonesse
user: Patapey
Same issue, missing Heartgem, can’t complete quest.
Tried resetting quest, doesn’t work, just ends up at same point.
Tried running Amrine again, but there’s no Heartgem for me to collect.
I think they’ve accidentally marked the Heartgem as no longer in use.
Server : Wood Perilous
Character : Fidjt
Same.
Character Name: Shalaleila
World: Calnogor
Region: US East
Mine is missing as well, disappeared as soon as I entered the altar area.
Character: Firekatte
World: Oceana
Region: US East
Same problem.
Character name: Illya Von
World: Pluto
Region: US East
same problem.
character name: Quarryboy
World: Ys
Region: US East
Same – Used the thing before killing the boss and it ate my gem =( now I cannot get another gem and stuck on main story line…
Help Amazon… ffs…
Same issue. No heart gem, no questy…
Name: Captain Kicked
Server: Jiuyou
US East
Same issue … -.-
Name: Iotama
Server: Emathia
Same issue
Name: Sergeantus
Server: Elphame
I wrote to support with this in Friday and still waiting for the answer, but i found topic on forum where issue was this same and someone wrote that support and amazon canto do anythink with this because they cant change somethink on player account. I will wrote again here if they sens me some info. I’ll try to exp another account. I think is only one solution.
Wtf they better not make me lvl another acc to lvl 30 just because their game is dog shit
Yay, I have my Heartgem back!
I stood in Cutlass Keys Village and reseted the mission twice in a row. And tadaaa: I found a Heartgem in my inventory. Hopefully this was not a coincidence and helps you.
No matter where u stand it works
im so happy of this shit game xd Thanks one more 
You are my lifesavior its actually works guys.
Awesome! I just reset it where I was and it worked - Thankyou!
You’re the boss. Thanks!