Yes. Once mined they are indestructible.

Being abstract constructs, Bitcoins are no more destructible than the number 2 is destructible.
They can only be transferred.
You cannot "unmine" them.

A bitcoin however can be taken out of circulation like every other means of exchange if the owner just refuses to spend it. Or the wallet is lost. But there is no equivalent of burning a $1 note in bitcoins.

Can someone correct me if I'm wrong?