Might goose do egregious damage inside overturning decorative rocks? (6)

I believe the answer is:

geodes

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'decorative rocks?' is the definition.
(I've seen this in another clue)

'might goose do egregious damage inside overturning' is the wordplay.
'GEODES' is hidden backwards within the letters.
However, I'm unsure how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for geodes that I've seen before include "Stones" , "Rock cavities lined with crystals - see dog (anag)" .)

I've seen this clue in The Irish Times.

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