Large mollusc with a shell lined with mother-of-pearl (7)
I believe the answer is:
abalone
This clue could be a double definition.
'large mollusc' is the first definition.
'abalone' can be an answer for 'mollusc' (abalone is a kind of mollusc). I'm not certain of the 'large' bit.
'a shell lined with mother-of-pearl' is the second definition.
(I've seen this before)
'with' acts as a link.
Can you help me to learn more?
(Other definitions for abalone that I've seen before include "produces an ear shell" , "Would you be able on a US shellfish?" , "Edible shellfish, sea-ear" , "Mother-of-pearl could have come from" , "One lives in a shell" .)