Does a shrunken item break its confines when unshrunk?

Question

When you put a shrunken item in a confined space and unshrink it, what happens?

Does it work like "Enlarge Person"?

If insufficient room is available for the desired growth, the creature attains the maximum possible size and may make a Strength check (using its increased Strength) to burst any enclosures in the process. If it fails, it is constrained without harm by the materials enclosing it— the spell cannot be used to crush a creature by increasing its size.

In which case, how do you define the item's strength and if it can break its confines? Otherwise, does it break the confines simply because it does not fit in there, provided it is of sufficient hardness?

For example, how does a shrunken cube of adamantine, lodged in the keyhole of a wooden door, behave when unshrunk? Does the door break? Does the cube break? Does the cube unshrink until it meets resistance?

Answer 1

Use object hardness in lieu of strength for the rules. Thus the adamantine cube would increase to it's normal size, wrecking the door lock. Whereas glass would stay shrunk.

However, this interpretation would give extra destructive power to the Shrink Item spell. Alternately have the item grow to meet the confines of it's container until taken out. This does mean that the shrink Item spell duration could be artificially increased.

The third option is to have an shrunk item magically pop out of the container much like something from a cartoon, using the rules the options above only when the item is fully prevented from escape.