Victorian Double Photo Brooch 1860 - 1880 very rare

Victorian Double Photo Brooch 1860 - 1880
I think the most fascinating thing about this brooch is that it features a ambrotype of a young man on 1860's clothing on back side, while on the front is a photo of who I believe is the same gentleman approximately 20 years later in 1880's dress. Brooch measures 1 3/4" across by 2" in height, with a collapsing gold "c" clasp and tube hinge - I've never seen a clasp quite like it before. Gorgeous 9k gold mount - looks like it should be a swivel brooch but it does not swivel. Definitely dates from the 1850's or 60's.Photography was an invention of the Victorian era, and photographic jewelry represented a permanent way to document beloved friends and family. Since the opportunity to be photographed was not as prevalent as it is now, a photo was a precious thing. Worn as brooches, cuff links and pendants, these faces from the past were most often mounted in non-precious metals under crystal or celluloid covers for protection.