I would be terrified lest it should fall into the wrong hands.

That sort of power is beyond anything known to science; picture if any government got their hands on it and began research. Oh yes; it may reveal secrets that could improve the lot of humanity; what invention since dwarf wheat has done that, I ask you?

First I'd probably hide it in some solid object - a bit of cast concrete or something. Eventually I'd get paranoid about that and start carrying it with me everywhere until I thought of a deposit box... and then remember that banks get robbed. I'd consider tossing it into a river or an ocean or in front of a glacier. Eventually, while walking the streets, I'd have to use it to flee from a mugger - and almost get run down by a car - and have loads of trouble on sidewalks.

So I'd hide it again and start thinking seriously about its destruction. Would a volcano be enough?