Crash Bandicoot (PS1) - Stage 22 - Jaws Of Darkness (100%)
Playing the 22nd stage of Crash Bandicoot, Jaws Of Darkness, to 100%, which means finding all the boxes without losing any lives in the process and is rewarded with a gem upon finishing the stage.
To 100% the stage you'll need the Blue Gem found in the Toxic Waste stage.