Pair of Filigree Mirror Backed Buttons Victorian?

So I don't specialise in buttons but i do have a vintage and antiques business so try my best to learn about everything that comes my way and recently that was a huge tin of buttons. I've had my grandmother's tin since she died 9 yeas agao and have played with them since I was a kid so I knew they were beautiful, collectable and sometimes valuable and because I also have a broader background in vintage and antique things I was fairly confident in picking out the Bakelite and dating items from style and material but I had no idea which were sought after or valuable and which were found in every button tin in England so for the last two weeks while everyone has been eating turkey or in our case goose and singing carols I've been researching my buttons one by one I will be posting some mysteries that I need some help with over the coming days but for now I just wanted to show you these which are my personal favourites a pair of filigree mirror backed art nouveau buttons found amongst a whole load of military and foreign legion ones that had been put into a bag within the tin I'm itching to clean to see whether they are copper , brass or something else entirely. Thankyou for taking the time to read my ramblings and I thankyou all in advance for your knowledge, experience and expertise which I will e asking to draw upon in the next few days