Police were still searching for a major work by the late US conceptual artist Gordon Matta-Clark, stolen from the Barbican gallery in London in May, as Museums Journal went to press.

The item was one of seven melted glass bricks that formed part of the artist’s 197071 sculpture, Glass Plant: Garbage Bricks, which featured in the exhibition, Pioneers of the Downtown Scene, New York 1970s.

The piece, on loan from an anonymous private collector, was taken on 22 May – the final day of the exhibition. A Barbican spokeswoman said that appropriate security measures had been in place.

The gallery is offering a reward for information leading to the recovery of the work, which was insured.

“The amount would depend on the type of information received,” said the spokeswoman. Lydia Yee, the exhibition’s curator, reportedly said that the theft had “caused a lot of people grief”.