In a large thread on the forums, players have flocked to grouse about how gems work in the game. The most common complaints about gems is their use of RNG, how difficult they are to level (especially since you can “fail” to level one up), their extensive use of time gating, and how easily they crack.
“The high failure rates when trying to level a gem!” one poster began. “As others have mentioned, it’s disheartening to see a few hours of gem dust farming go down the drain after a few attempts to level a single gem that failed with nothing to show for your efforts. When we upgrade our gear, it never fails. So it seems odd to add this mechanic when we level gems, as it just makes players waste gem dust, flux, and their time.”
Source: Official forums. Thanks to Enikuo for the tip!