Help needed on age of these brooches please

I have several pieces that were included in an auction lot that I would like to confirm the ages, if possible and would welcome the opinions of the experts here. I will post two threads on them. First up, I have a brass enameled piece that was labeled "Victorian Buckle Brooch" but obviously it is not a buckle. It is 2 3/4" wide, 1 3/4" tall and has a C-Clasp. Is it a sash brooch perhaps? Is it really Victorian?

The second one is 3 3/4" wide, 2 1/2" tall, has a roll over clasp, with an embossed design and either cut steel accents or marcasites (I think cut steel) and the brown seems to be enamel. 1930's? I don't think sash pins were a thing by then, so just a big brooch?

The third one, I don't have a clue. It's made of pressed lightweight metal with blue glass, a riveted back with a roll over clasp and is 2 1/2" in diameter. Any idea on its age?

Thanks for looking and for your opinions, as always.

 

The lovely enamel one and the marcasite look 20s ish. I'd not really call them sash brooches, but hey. The blue, a bit later. 30s at the earliest, might even be early 50s.

 

Thanks for the information OBB. I was thinking 1920's was too early for a roll over clasp but you would know better than me. So they are just brooches then. I was pretty sure the blue one was later but the back really baffled me.

 

The enamel one is fab.So pretty!