This one could be a bit of a challenge.
American Standard "25 year" 14K gold filled. "Mongram quality" whatever that means. No patent date. No signature on the crown.
It was starting and stopping when I bought it but when I demagnitized it, it began running and keeping time well. There's a little bit of brassing here and there but, like most of these early ladies watches, its in pretty good shape. No band.
The movement is AAI and there is, as would be expected I guess, no date code. There is, however, a trangle with what appears to be an "18" or a "48" inside of it. I focused in on it below in the 5th image. I can try to get a better picture of it if you need it but my hand isn't very steady on the camera.
I'm at a loss on the model and date of this watch. The movement range is 1921-1923 so I picked 1922. I'm going to guess one of the Lady Maxim's because that's what most of the ladies watches around this time seem to be and there's a huge variety of them. Some of them have the same case shape and general style as this one. The ads haven't yielded anything that looks exactly like it but I'm getting the impression that isn't much of a surprise with some of these early models.
Honestly, I don't have a clue. I think this is one where I'm going to have to sit back and watch the masters at work.