Brass Sconces - Antique?

[rustyattic]

Picked these up the other day.   They're brass and measure 17x10x5.  There's a small diamond mark on the back with what looks like an "o" or "d"  (I can't get it to show on the pics)  When do you think they were made?

[ThankfulE]

You should post a picture of the back, too, and a close up of the makers mark.