Best spells to protect a phylactery

[DementedFellow]

As seen in this OotS page (http://www.giantitp.com/comics/oots0656.html), we see Xykon say that he loaded up his phylactery with so many abjurations that he doesn't even remember what half of them do.

What spells would you put on a phylactery to shield it from as much damage as possible? I'm looking more for actual spells rather than the usual "I turn it into water and pour it into the ocean" responses.

Bonus points for spells that can be made permanent.

[Zanos]

Well, hardening for one. A 20th level caster will increase the hardness of it by 10, giving it hardness 30.

[Lanson]

I would say spells "Hardening" and protection from x spells made permanent onto it would do alright, though the protection from x spells might not work on objects. Magic Aura, Nondetection, maybe explosive runes and contingent teleport spells "whenever anyone but me looks at phylactery, teleport it to X location if it starts in Y location" and have a ring of well trapped/stocked dungeons that it teleports between.

Edit: Some of these may take some DM discretion, as I dont believe they all work on objects.

[Lapak]

Invisibility, Nondetection, and Antipathy are the first three things that pop to mind.

[jedipilot24]

Well from this (http://www.giantitp.com/comics/oots0831.html)comic, we know three of the spells.