Dating c.1770s, it is remarkable this box has been so well-treasured. With a generous 18k mat and the original slightly convex cover glass, the portrait is of a woman of Noble class, likely a courtier of Marie-Antoinette's and Louis XVI's inner circle or certainly acquaintance. The box into which her original portrait is installed is a superb layering of paint and varnish, in a flat color which from the underside one can tell was once blue to bluish-green, but which has faded evenly to an almost hunter green in all light-exposed sides/top. From side views you see the layering is thick, and firmly affixed to the inner shell lining which is quite astonishingly undamaged by time. Full measurements are noted on the photos - her face is a tiny 1/2" from chin to hairline.
Very good to excellent condition for age and type, as noted above. I can see one tight fine hairline in the Vernis Martin top, radiating from about the 2 o'clock position right of woman's lace bonnet - a shrinkage line, it is not really a crack. I've shown from all angles of view, the astonishing absence of chips or bug bites. No loss to the glass. A few dust particles might be on inside of glass, which seem to have caught our photo lights and appear as tiny white dots on our photos. I have never removed her from box or frame to clean the glass. Amazing detail to her gown and clothing - I do not see a signature. It is sometimes the case if I open them to clean glass, I find a tiny signature on outer rim, beneath the gold frame, or even thin document inside which provides identification, but I leave that to you. I hate to pry gold frames unless the glass is quite bad. She displays beautifully.