Identification on a necklace and unusual spring clasp please?

I cannot find anything about this piece. It's unmarked as far as I can tell. I have never seen a spring clasp without the thumb knob. Can anyone help? Much appreciated.

 

I can't tell what your is, but I have a 60s simple opal pendant on a gold chain, with this type of clasp - with no latch hold. Mine is by Krementz, and came with the original box. Also, I have found other Krementz pieces that match mine (different stones, same setting), that I have confirmed 60s. I have an older piece (I've dated as 30s, by other elements on the necklace.) with a similar spring clasp without a latch, but it is a much larger clasp, and easier to manipulate! So that doesn't fully help, but maybe points in a direction to look...

 

I came across this photo on another forum. The person posting it did not include a link but stated it was an ad dating from 1889 (which does NOT mean that that is how old your necklace is). Just thought I'd share, for reference.

 

I've always called that clasp a "nibless clasp" (it doesn't have the nib), but I've notice other people call it a "thumbless clasp". For me, my first guess when I see a nibless clasp is that the piece is 1930s--they were very popular then. But, again, that's only my FIRST guess, which needs to be confirmed by other aspects of the piece.

I don't see yours as being 1930s. It reminds me of that standard Monet or Napier gold-textured bead necklace strung on chain. But the clasp doesn't fit with that. And it is sure a pretty clasp, with that engraving.

I'm eager to see if somebody else can place the date. If forced to guess, I'd have to say 1960s or 1970s, and that's based on the texturing of the beads and the goldtone chain.

P.S. I love what Donna @The Vintage Vendeuse found!!

 

I think your necklace is 1960, early-ish. BUT I have seen that kind of clasp on many eras of jewelry... 40s... even a 50s Trifari... they are wonderful!