What does the cryptic crossword clue "Cyclone had disturbed rock (10)" mean?

The wordplay uses an anagram. anagram of CYCLONEHAD ("Cyclone had") [anagram: "disturbed"] = CHALCEDONY The answer is CHALCEDONY.

Cyclone had disturbed rock (10)

Guardian Cryptic #29375 | 14 Across | 2024-05-06 flower