Oops. Didn't realize this wasn't changed yet.

Gemstone Mine is a different Aether Hub. Hub didn't really feel like a proper splash enabler as much as I would like, so shifted it to the mine so you can get multiple instances of colored mana out of it. As the trade off, you can only use it thrice, so sequencing and when you play the land can be important. I'm quite a fan.

... it's been this way in paper for a minute, but I never updated it here with reasoning, so here you go.