I can't figure out how to solve the puzzle to open the shortcut and it's annoying me so much. I know it is something to do with the skulls on the wall, I just can't tell what eyes mean what gem. (Edit: just figured out that that isn't the clue and now I am completely lost.)
Viewing post in Curse of the Amethyst Skull comments
I tried brute-forcing it (which is kind of shameful behaviour for a puzzle game ^^") but that led me to stumble upon the real answer. Clues in rot13, in increasing order of specificity;
Clue 1: Gurer'f ab pyhr uvqqra naljurer va gur qhatrba, orlbaq gur vgrzf gurzfryirf.
Clue 2: Pbafvqre gur anzrf bs gur trzf
Clue 3: Pbafvqre gur vavgvnyf bs gur trzf, naq jung gurl pna or hfrq gb fcryy bhg
Answer: Hfvat gur svefg yrggre bs gur anzr bs rnpu trzfgbar, fcryy bhg 'bcra'