Thanks for the hint! I must be very unobservant here as I went back and examined/used anything that looked remotely out of place and still have turned up empty. This will undoubtedly be one of those moments where the answer will be so obvious I wondered how I could have overlooked it.
If you would like the answer...
[SPOILERS]
In the Chamber of Knowledge (the library in the Azure Palace) the wall on the left has a mural of clouds and one of the wall tiles is upside-down TAKE the upside-down cloud tile to remove it and USE the ROSETTA STONE on the writing to learn the spell OPEN SESAME. USE O. SESAME on a rock leading into the tower
I have uploaded a playthrough of the game:
Thank you for the enjoyment and the help.
I'm also looking for all the ways to meet a terrible end as that's also part of the fun with these games but I haven't completed the challenge to be killed by every monster so I'll be hunting down what has to hunt me down first.
I have also done a video of the ways to die:
An audio error appears to occur with the writing sound effect (as text is displayed) if you rapidly click on the genie's wishes too (it lasts until you quit).
Once again, thank you for the enjoyment from this game and congratulations on finishing it! I look forward to your next project!