To summarize, David suggested that the pearl and diamond stomacher worn by Queen Mary in the above photos dated 1902, 1905, 1935, and 1937, may have originally belonged to Princess Mary, Duchess of Gloucester and Edinburgh. Beth found that Princess Mary left her niece and goddaughter, Princess Mary Adelaide, Duchess of Teck, a pearl stomacher in her will. Princess Mary died in 1857 and Princess Mary Adelaide died in 1897. So if Princess Mary Adelaide left the stomacher to her daughter, Queen Mary, it fits that the first picture we have of her wearing it is in 1902. Here are a couple of close-ups of the stomacher in question but the second pic has the bottom cut off.