Engagement photo of Prince Albert Victor, The Duke of Clarence and Avondale and Princess Victoria Mary of Teck, 1890s. He died before they could be married and she married his younger brother George, Duke of York (later becoming King George V and Queen Mary).
Queen Mary wearing Marie Feodorovna's bandeau (she's replaced the sapphire with the emerald carved brooch), her emerald art deco chocker (later worn by Princess Diana), the Cambridge emerald earrings and scroll brooch, another emerald and diamond brooch and some diamond collet necklaces.
I've never seen this photo before. Queen Mary, wearing the diamond lozenge tiara with thirteen upright pearl spikes, and Lady Bessborough, wearing her lovely art deco tiara, which she sometimes lent to Rose Kennedy.