Crossword Genius

Describing a boom in unusual coins? (5)

Ross

I believe the answer is:

sonic

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'describing a boom in unusual coins?' is the definition.
I can't tell whether this defines the answer.

'unusual coins?' is the wordplay.
'unusual' is an anagram indicator.
'coins' is an anagram of 'SONIC'.

Can you help me to learn more?

(Other definitions for sonic that I've seen before include "Relating to the speed of sound" , "Involving sound waves, say a boom" , "Hedgehog" , "Using waves" , "Like mine, possibly" .)

I've seen this clue in The Globe and Mail.
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