Important elements seldom seen where we live (9)

I believe the answer is:

rareearth

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'important elements' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'seldom seen where we live' is the wordplay.
'seldom seen' becomes 'rare' (something seldom seen is seen rarely).
'where we live' becomes 'earth' (I've seen this before).
'rare'+'earth'='RAREEARTH'

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I've seen this clue in The Irish Times.

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