The mourning icon you see here dates as early as 1840, as late as Napoleon III era (c.1850-70, roughly). It's made more in line with the earlier dates, a foil backing and the addition of both seed pearls and slightly larger pearls, 18k gold wires and a cast 18k gold monogram of intricate design. The lock of hair a reddish blond, light brunette, seems likely to be that of a child. Remember no photography before 1838, when Daguerre developed the very first method of photography, and for the most part, no popular photography until later 1860s and beyond. A lock of hair would have been very likely the only remnant and memento of the person who died. The icons in this one include a moon, the reference to celestial destination; seed pearls which represent the tears of the mourner.
Very good to excellent condition for age and type. I can see wear to the brass mat in form of a few dark spots that did not instantly polish, but will likely with a little more elbow grease than I'd applied to it. The backing is not broken, no cracks. There are a few tiny seed pearls missing around the moon, but the 3 larger pearls holding the lock of hair are all intact. Measurements noted on the photos, it is 5" (plus bale) x 4.5" and is .25" thick overall. The oval aperture is 3.25" x 2.75". Frame and piece in total are quite elegant, still.