My Grannys Watch

This was my late Granny's watch. I know it's marcasite piece (at least I think it is)! I wondered if anyone knew when this kind of watch was made and any kind of history on it. I am not sure if they are metal bits of decoration on the strap and around the watch face or if they are tiny Diamonds? They do glisten when you move the watch around, I don't know if that helps? It just has Stainless Steel printed on the back.
Probably more importantly, on the face it says:- PERFEX and lower down, it says:- 17 JEWLES INCABLOC.
My sights not the best. so it could be spelt a bit different...………….it actually could say something completely different, like SWATCH2019, but I don't think it does!
I don't think this is working!