has been and has gone

[selinat]

Could you please tell me what's the difference between the following two sentences:

1. His parents are very worried, he's been missing for a week now.
2. Has anyone seen my calculator? It's gone missing.

Thanks in advance

[Tdol]

Gone - refers to the action of disappearing
been - refers to the state of being absent:

His parents are worried- he's gone missing.
How long?
He's been missing for hours.