How can I make an object (nearly) indestructible?

Is there any way to protect an object from destruction, as a player? If so, how expensive would it be?

Let’s say I become a lich — is there any spell/ritual/artifact/other that can make my phylactery indestructible? (Apart from hiding it, obviously.) I’m thinking of Voldemort’s Horcruxes, wich were pretty much a PITA to destroy.

Any means mentioned in official source is good, and needing to use multiple things together is fine.