I recently purchased 6 gilt spoons from a friend without provenance. They are very unusual for a number of reasons. They seem to have elements from both French and German flatware. The maker's mark a B in a lozenge with a pellet above and two smaller pellets below looks like a typical French mark, used only on first or second standard solid silver. There is a second mark struck above and below the maker's mark. It is not French and there is no counter mark on the other side. It appears to be an animal head looking straight on with floppy ears, or perhaps a mustached man wearing a helmet in a circular cartouche.

The spoon is marked on the front between the ornate areas, an odd place to mark them. They are engraved with the owner's initials on the back. The ornate parts are not repoussé work, but are presumably swaged or forged on.
The point of the bowl has a very large shelf, something most often found on French spoons.

I would date the spoons around 1820, but I could accept a little earlier or later. If this date is even close to being right, the gilding is fire or mercury gilding, which would use a fair amount of gold as opposed to electroplating. Although I have never seen a study that tells how much gold would be used in this method.
I should add the spoons, when first received, seemed to be very excellent quality, the gilding seemed excellent quality, every bit as nice as any I have seen on good quality Augsburg or Strasbourg pieces.

Which is why I was shocked to find they are not silver. First I tested a small worn spot on the back of one bowl. It tested, at best, to be very low quality silver. Since acid testing is not very accurate, I took them to another friend to try X-ray fluorescence testing.
The small worn spot was shot, so the results would just be the metal content of that small area. The results were Copper 46.01%, Gold 30.3%, Zinc 11.39%, Nickel 10.29, and less than 1% each of Br, Co, Fe, Ag, Sn. Of course the machine is set to come up with a total of 100%, and it did. But there is certainly not 30% gold in the spoons, it is just referencing the gold on the surface. The mixture of copper, nickel, and zinc is, I believe, the formula for white brass, sometimes used as the base metal for fine quality French electroplate.
Of course this brings up all sorts of questions. If they were made in Germany during the Napoleonic era, when a lozenge mark was more likely to be found, what are the other marks, and who was the maker? But the real question is why would a silversmith would spend so much talent and produce such fine looking spoons, and then not even use 12/16 silver, which would have required about 1/2 oz of pure silver per spoon?