Times cryptic hotline offers 'rock within rock' (8)

I believe the answer is:

xenolith

'rock within rock' is the definition.
(rock trapped in another rock)

'times cryptic hotline' is the wordplay.
'times' becomes 'x' (multiplication sign).
'cryptic' is an anagram indicator (a cryptic or obscure order of the letters).
'hotline' is an anagram of 'enolith'.
'x'+'enolith'='XENOLITH'

'offers' is the link.

I've seen this clue in The Independent.

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