Antique 18th Century French Portrait Miniature Snuff or Patch Box, 18k Gold Mat and Medallion

A perfectly delicate portrait in miniature, mid to late 1800s, signed by artist, "Lauris", the woman would have been a noblewoman of the Louis XVI. In fine fashion of her era. Her portrait is mounted on a burl wood snuff box, most likely - shell liner, or possibly a patch box. The mat is 18k, rather thin in nature and shows a few imperfections. There is also an 18k gold medallion set into the back side, very interesting and likely to have significance that is beyond my historical knowledge. A beautiful little box and painting, artist Lauris has captured her essence in a face only 3/8" from chin to hairline. Full measurements noted on photos. Very good to excellent condition for age and type. This is one I've had for a long while, the very thin old convex cover glass had a crack across is. It's nearly impossible to find a replacement for the very old cover glass panels, owing to size and the thin measurement of it. Fortunately, ordering a sapphire watch glass for something else made me