Do you want some general information

Hint 1 of 4:

You must find all ten to finish the game.

Hint 2 of 4:

If you touch an empty Pentacle space in the rack in the Vault Vestibule,

Hint 3 of 4:

the location of that Pentacle will be displayed.

Hint 4 of 4:

All Pentacles are purple.