Gauntlet of Shar. what am I doing wrong?

[lisa fullmer]

I've completed all three challenges, received the three gems, found the secret room in the library and taken the spear. But the vault door still won't open!
And it's put me at a stand still. I can't progress any farther in the game. What else am I supposed to put in that alter?

[His Divine Shadow]

Did you put the three orbs in the altar after taking the platform down to the door?

[Izuzul]

There is a big demon guy to kill, not part of the trials. He has an orb/gem by his throne iirc.

[seeker1]

You need 4 gems in total. 1 for the elevator, 3 to open the door downstairs.