Can you help me identify the era of this photo?

Yes, they are wonderful - look like pagoda sleeves? If so then latest is likely mid 1860s, I think - but could very well stand corrected!

 

same woman here as well: https://mohistory.org/collections/item/N17332

 

possibly the brooch, lace cover are photographers props. the book definitely is. props symbolism was popular.
or the pictures were taken the same day, and these women know each other. same daguerreotype cases as well
https://mohistory.org/collections/item/N17334?view=zoom

 

The simplicity of the frame points to an earlier era (1850-1860), confirming your thinking.

But it doesn't really look like a dag; more like an ambrotype. ??

 

Yes, and, btw, the Missouri Historical Society is one of the most outstanding Historical Societies. Most of my family is from Missouri, by way of Virginia, then Kentucky. So I use MHS for genealogical work.

And I did see they are identifying it as a daguerreotype, and I really wouldn't question them, but it does surprise me. Dags have a mirrored finish, and you can easily see that in most photograaphs of them. It makes them hard to take good pics of them. From Google: "The Daguerreotype image has a magical, mirror-like quality. The image can only be seen at certain angles. A piece of paper with writing will be reflected in the image, just as with a mirror." So, they must have had an excellent photographer who took pictures of those dags. Those are gorgeous reproductions. Without a great photographer, you will see the mirroring effect in the reproduction, or else the image itself will appear cloudy or somewhat unseeable.

And ambrotype is also on glass, but has a black backing that makes the image appear. Ambros came a little later.

My first collectibles were dags and antique real-photo postcards. Still love them.

 

It says in the photographer's bio that he did daguerreotypes exclusively, even when they went out of fashion and people started doing wet plates. Daguerreotypes are made on metal plates covered in silver and polished. They are so distinguishable you can't mistake it for anything else. I have plenty of books on daguerreotypes, they ale have great reproductions. You just have to put a dark fabric in front of it to photograph them.