'The Adventure of the Beryl Coronet' is a Sherlock Holmes short story by Sir Arthur Conan Doyle, first published in The Strand Magazine in May 1892 and included in The Adventures of Sherlock Holmes. The story follows a banker who entrusts Holmes with the investigation of a stolen and damaged valuable coronet, left as collateral by a high-ranking client. When the banker's son is found in possession of the damaged jewel, Holmes must untangle a web of family secrets and deception to uncover the truth behind the theft.