As you say this is all so very interesting. I read in Leslie Field's book that they were originally buckles which Queen Mary then used to mount on the diamond collet bracelets - one of which used to have Prince Albert's miniature as it's clasp.
--Previous Message-- : What I am intrigued about is that at least two : of the images you posted Nellie have : identical diamond borders - the circular : borders that is. Presumably King William and : Queen Adelaide decided on the same design : for each style. : I am intrigued as to why some were square : (or rectangular) and some were round. : Perhaps the jewels were intended for : different purposes and yet it would appear : that both designs were used (perhaps : eventually) for bracelets. :