This is a beautiful piece, which I was told by the dealer who sold it to me, was a button. Imagine having a piece of clothing with buttons like this. Anyway, she says it was altered to be a brooch, and that alteration has been done quite a while, because the brooch has the older "t" hinge, and "C" clasp. It's a wonderful piece which speaks for itself. It does have clearly visible hallmarks, which declare it to be British Sterling Silver, made in Chester, in 1901, by the maker R & P. The brooch measures 1 inch and 3/8 in diameter.
Another shopper has this item in their Cart or Wish List.