"Besides causing damage to creatures, the fireball ignites all combustible materials within its burst radius, and the heat of the fireball will melt soft metals such as gold, copper, silver, etc. Items exposed to the spell's effects must be rolled for to determine if they are affected.
Items with a creature which makes its saving throw are considered as unaffected."
I looked it up before I posted
Edit: As an aside. THIS is the sort of language 5e would have used if 5e fireball was supposed to be able to destroy worn items.