A qarina may be a word in the utterance or a circumstantial or rational clue supplied by the situation. Its purpose is to determine the intended meaning, not merely to decorate the expression.
In «يَتَكَلَّمُ بِالدُّرَرِ», the act of speaking points away from physical pearls toward eloquent statements, functioning as a verbal contextual clue. Elsewhere the situation itself can supply the clue.
A resemblance or other relation alone is insufficient: the interpretation must also account for why the literal meaning is not intended.