For many, the enduring image of Queen Victoria is of a monarch in mourning, stern-faced and bereft in her black gown and white headpiece after the death of her beloved husband, Albert.

Very few pictures capture the young, vibrant woman she had been – when she ascended the throne in 1837, aged 18, photography had barely been invented. But such images do exist, and to mark the 200th anniversary of her birth this Friday, the Museum of London has unveiled exclusively for the Observer two rare photographs never before seen by the public.

“It’s a younger, fresher, more fashionable Queen,” says Francis Marshall, senior curator. “You wouldn’t think it’s Victoria.” Locked away in the museum’s photographic department for decades, they are “as special as a painting” Marshall says, in part because they were rare examples of stereoscopic daguerreotype images. As a result, they are one-offs and impossible to reproduce.

It's a younger, fresher, more fashionable Queen. You wouldn't think it's Victoria Francis Marshall, curator

Taken in 1854 by the French photographer Antoine Claudet using two cameras side by side, the photos were mounted on steel and would slot like slides into a viewing device – not unlike today’s virtual reality goggles.

“You would put the goggles in front of your face and see the images blend together – and that created an illusion of three dimensionality,” says Marshall.

The pictures are among the most significant prints in the museum’s 150,000-strong collection, he says, because not only are they two of the very earliest images of Victoria as Queen, then aged 34, but they also reflect her fascination with photography. At the Great Exhibition of 1851, the Queen and Prince Albert were captivated by the photography on show, he says. “They even learned to make their own prints.”

The second pair of stereographic daguerreotypes of Queen Victoria taken by Claudet in 1854. Photograph: Antoine Claudet/Museum of London

The royals privately commissioned Claudet – one of the stars of the Great Exhibition – to take stereographic daguerreotypes of them both – and they even granted him a royal title: photographer-in-ordinary. “It would be like the Queen today appointing a virtual reality laureate,” says Marshall.

The photos were never intended for public consumption – which is part of the reason they have never been seen – and will not be on display at the museum. Rather, they would have been early examples of personal photographic mementos, kept in leather-bound presentation cases. It’s believed one of the cases, inscribed with the royal coat of arms, might even have been intended for Prince Albert as a gift.

Current royal photographer Hugo Burnand – who was on duty at this weekend’s wedding of Lady Gabriella Windsor and Thomas Kingston – says daguerreotypes of the era are sometimes even “sharper” in image than today’s digital photographs. “It’s the aesthetic and the emotion in the photographs that makes them so enduring,” he said.