I've found exactly one other antique paper lace valentine with a mirror of this sort, c. 1840s, here with mirror bordered in wreath of hand-colored die-cut flowers. And here with a silver die-cut ribbon just above it, which looks quite a lot in form like ribbon-tied hair wreath memento of the era. I'm just a sucker for these, such pretty and delicate things delivering sweet sentiments. And here a pasted verse on the front and then a handwritten one inside, beginning with this excellent bit: No rubies on the Indian shore / Outshine thy noble mind. And then, to end: Absent but not forgotten. 

5 1/2" x 3 5/8" closed. Good condition, with one small area of loss to paper leace along left edge near top as visible (a few leaves on the tree I believe.) The pink paper behind it not glued, never was, just inserted.