When were these sorts of brooch clasps used?

[Better Dresses Vintage]

Hello,

I've never seen this particular style of clasp before. You press in at the end to lock the mechanism in place (pull to open). It's not "automated" -- it doesn't spring open or closed. The brooch itself is shell and faux (I think) pearls. The pearls are wired in place (two are missing due to broken wire). Anyone have an estimate on the date? There are no markings. Thanks. Liza

 

[cmpollack]

The trombone clasp was patented in the mid 19th century, but continued into the twentieth century (the 1950s!) in Europe. The wired construction and back metal plate look early 50s or maybe late 40s to me...

 

[Better Dresses Vintage]

Ah, new terminology for me: "Trombone clasp." The 40s/50s date would make sense in the context of where I found it. Thanks, Carrie!

 

[Sky Ranch Vintage]

Wow, I've never seen this type of closure before. Thanks for asking this question as I've learned something new!!

 

[Linn]

They are frequently found on French (and other European) pieces and I believe are still used occasionally. I agree with Carrie's dating.

 

[Better Dresses Vintage]

I have already listed them as being from the late 40s to 50s, based on your helpful information. Thank you!