Such appearances are immaterial (11)

I believe the answer is:

apparitions

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'such appearances' is the definition.
'apparitions' can be an answer for 'appearances' (apparition is a kind of appearance). I'm not certain of the 'such' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.

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