That's a kiln-fired enamel plaque mounted as cartouche on this fine old French carved horn table snuff box, and it's framed in a mount of 18k yellow gold. Dating early to mid-1800s, the enamel work is marvelous. See that lovely little dog, too? This process, which I've written about many times, is one only accomplished with the skill of years and years of practice. The enamel powders are various shades of muddy mauve, taupe, blues, not the least resembling the color they will become once the kiln melts them into the glassine or porcelain like finished product you see here. So an artist is layering on stroke after stroke, working quite literally blind as far as the colors and spacing of the finished outcome he/she hopes to achieve. It is the memory that guides the hand in this art. And subject to such whims of nature and memory, it's always amazing to me that they come out with anything but a glob. I've tried this art, myself, and believe me, it's very difficult. I mostly get globs. The nature of the process is part of the reason why these old kiln-fired objects have such a following and bring the prices they continue to bring.
Very good to excellent condition for age and type, with very little flaw to note. You see some small natural 'horn' flaws but not anything serious or damaged. The gold mat to the mounted enamel has very slight lift to it on perimeter, visible in our images, but it does not appear to have any dents so we can assume it is the original form. The enamel oval plaque has not a bit of damage. No chips or cracks or hairlines. Quite rare to find in such great form. A wonderful 19th century table snuff, large at nearly 4" long!