Crossword Genius

As is nacre, surprisingly (7)

Ross

I believe the answer is:

arsenic

'as' is the definition.
('arsenic' can be a synonym of 'as')

'is nacre surprisingly' is the wordplay.
'surprisingly' is an anagram indicator.
'is'+'nacre'='isnacre'
'isnacre' is an anagram of 'ARSENIC'.

(Other definitions for arsenic that I've seen before include "Poisons in scare" , "As briefly identified" , "Poison found in races" , "Famous stage comedy ''. . . . . . . and Old Lace''" , "Powerful poison" .)

I've seen this clue in The Guardian and The Telegraph.
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