Featured Cut Steel Brooch Find

Came across this interesting cut steel brooch. The moulded or cast glass element in the middle has me stumped on the dating as I've not seen one like this before. Sorry the phone pics aren't great but has anyone seen one like this. Hand made hinge, brass back and severely vicious pin. Later part of the 19th century, or possibly earlier?

 

The hinge looks early 20th to my eye. Is it possible the blue was a later addition?

 

I think it is unlikely as the riveting matches and the form matches the backplate shape as well, it can rotate a bit as the stud is now a little loose.

For some reason with cut steel jewellery there seems to be an incongruence between general hinge dating and what is written about these. The studs on this are 12 facet, which tends to indicate a mid/late 19thC dating, that said the design isn't very complex and the glass is most odd. The very late 19th century examples are commonly found with 5 facets, and earlier Georgian ones with 15 (sometimes screwed and not riveted). Also it is generally considered that cut steel jewellery production all but ceased by 1900.

Here's and example: https://www.antiquejewellerycompany.com/shop/georgian-cut-steel-brooch/

Note the design is more complex but the smaller studs match and the hinge is near identical. Not sure I would push the date as far back as they suggest, but it gives an indication of what I mentioned above.

 

Mid 19th IMO. The very long pin and simple hinge points (pun) towards that era.
For the turquoise part, I saw an antique bird brooch with pavé turquoise glass rosettes held by cut steel pins.
Missed the buy and didn’t save the image

 

Unless that pin stem is a replacement, and it doesn't look like it, the whole thing is 140 years old give or take.

 

Thanks, this was my initial thought too, but the glass and relative lack of detail threw me. I will keep digging and see if I can turf up anything on moulded glass. There are numerous glass cabochon ones, but nothing like this. Wondering if it's a French piece.