Old Jewelry Help Please

[g...@weeks.pdial.interpath.net]

I have a unique pendant that I need help with.

It is an oval 2 inches by 2 1/2 inches. The front is flat, and is glass.
The back convex and the whole unit appears to be made of brass or gold
plate. Inside the pendant is a hand painted portrait of a man in what
appears to be colonial era (I'm no expert on this) dress. The most
unique thing is a small oval glass window on the back, about 1
inch by 1/2 inch proportional to the overall shape of the pendant. The
window is obviously designed to allow light illumine the face from
behind. There is fine detail surrounding the smaller oval as well as the
larger oval in the front. The quality of the painted portrait is
excellent.

Can anyone tell me anything about this piece?

Are backlit portraits on glass like this common?

Thanks for your help.

[Murray Robertson]

Hi. The window, if it from this period, would probably have been used
to display a lock of hair, possibly from the person in the portrait
or from the person who gave the gift. This was considered a romantic
token.