The ordinary share certificate of Boulder Perseverance Limited, issued in London in July 1939, is part of a series of certificates held by Louis Duvillier in British mining and exploration companies. Boulder Perseverance evokes, through its name, an Australian or South African mine — the term 'Boulder' being frequently associated with the goldfields of Kalgoorlie in Western Australia. The nominal value of £5 per ordinary share corresponds to the standards of mining companies listed on the London Stock Exchange in the 1930s. This document, with its serial number 1148, bears witness to a substantial issue intended to finance extraction operations. Collectors of mining scripophily will particularly appreciate this certificate for its historical context and its provenance consistent with the other Duvillier documents.