Metal splinter left moving nearer to heart (6)

I believe the answer is:

silver

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'metal' is the definition.
(silver is a kind of metal)

I don't understand how the rest of the clue works.

(Other definitions for silver that I've seen before include "symbolically a twenty-fifth" , "Change - Ag" , "Pirate" , "Precious metal (for second place)" , "Twenty fifth anniversary metal" .)

I've seen this clue in The Telegraph.

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