I think this is the earliest piece. As you can see, it's not only dedicated to Mom, it has a religous theme too. This piece still has it's original box, so I suspect that this was something Mom treasured and never took out of her jewelry box.
Another common type of both "mother" and "name" jewelry were mother of pearl brooches generally shaped like leaves. 14K G. F. wire was fed through a hole and the word "Mother" or a name was spelled out on the front of the brooch. I've seen these attributed to Victorian times, but I remember buying something similar at the Illinois state fair back in the 50's.
As sort of a take off of that piece, I had this interesting sterling silver leaf with the word Mom stamped at the base. I've never seen anything like it and would be interested to learn more about it.
In the 50's and 60's I remember these "mother" brooches were popular. The brooches were either heart-shaped or circle-shaped and each stone placed in it represented the birthstone of a child. Grandmothers also received them to represent the birth of grandchildren. Clear stones were used if there weren't enough birthstones to fill the piece. As a result, the brooches themselves are common, but no two are alike. While this brooch could have belonged to a mom with a very large family, I suspect it was actually given to a grandmother.
I guess as the years went by, Mom was often considered more of a pal. I have an interesting "friendship" pin dedicated to Mom with a 1996 date on the reverse. It's a very sweet sentiment.
While most lockets are on chains they are also sometimes made as brooches. I've come across a very modern brooch with a similar purpose. But rather than hiding the picture of your loved one behind a hinged door, you can wear it proudly. Old ideas revisited for the modern age.
Hope everyone has a happy Mother's Day!