I wasn't going to post on this again 'til I'd looked in one of my bigger books, (which I haven't had time to do yet.) but...
I'm not sure these two photos were taken in the same studio. Maybe the same address, maybe the same photographer, maybe he had lots of props...
As to mourning practices and jewellery.... there was a whole industry producing the stuff, I can't find any reference to a widow removing her wedding ring when her husband dies. There are, however lots of reasons why a married lady or widow wouldn't be wearing a wedding ring.
Currently reading from 1830's, (some plague, can't remember which, typhoid I think) widow was in black for 6 months, then lavender for another 6 months, with black gloves.
Mother was in black for lost children the same times. These ladies were upper class, society ladies and much younger, so maybe older women mourned longer and maybe middle classes were less inclined to spend too much money on "second stage mourning". Lots of variables....
Just putting in this lot to confuse you all.

Just kidding, I just feel that the more information we have the more informed our guestimates can be.
Leonie.