pixel_player378406685
Trying to understand your quesrion.
Are you saying you've opened the Ruby and Amethyst gates & in one pass through that location? If so, then you simply don't have enough red rings to open the green gem gate. Either leave the Reward Hall open by NOT clearing the middle tile & go dig more rings or break the middle tile to let the mine refresh, dig for more rings, & return to the Hall once refreshed.
You don't HAVE to do every gate in the Rewards Hall, just one per "level" will give you access to the breakable center tile.
IF the above is NOT what you mean & the gem gate won't ooen, despite having enough rings, then you need to create a SUPPORT TICKET:
https://portal.pixelfederation.com/en/diggysadventure/support
Scroll past the white search 🔍 bar & choose a category to begin the form.