I have always thought that the holocrons within Star Wars looked really cool, and the information that they hold makes them even more awesome!
I have created a few different versions of the holocron depending on what you want to use it for:
A completed holocron with the corners in line with the rest.
A completed holocron with the corners turned as when the jedi are opening the holocron.
A holocron with the corners off.
A holocron that has no corners as well, but has pegs sticking out with a small tab on the pegs where the corners would go (the "jedi holocron base" file). Which I have also included the corners separate with the holes for the pegs with a slot for the tabs to fit into so you can attach the corners and spin them around.
Depending on your printer and the settings you are using, you might need to use support for the overhand on some of the parts.
May the mass time acceleration be with you!!