... Did they first fire-gild the object and then inlay the niello?
Without seeing the articles, I can only speculate on a couple
approaches. It is possible to apply niello to an article that already
has already been gilded, but probably not the other way around. The
melting temperature of the niello is low enough that if there were
any proximity to an amalgam paste containing mercury, you'd get a
mess as the two compounds reacted to each other.
As to the problem of grinding away the gold after niello inlay,
niello can be ground to a powder and inlayed much the same as glass
enamels, that is, carefully filling the areas, melting by heating the
entire article, then repeating the process until a level surface was
attained. It would then even be possible to burnish the entire
surface, if the niello alloy had sufficient lead content to be
slightly malleable, which would tighten up the visual effect of one
color metal meeting flush with the other, everything at the same
On the other hand, careful and practiced technique could suffice to
make it possible to finish the surface by a technique I'm reluctant
to divulge here on Orchid (I know, shame, shame, but why shouldn't I
get a chance to get some credit for this skill before everybody is
doing it?). I have inlayed neillo in patterns as shallow as 1/100th
of an inch, overfilling and removing down to level with the metal
being inlayed, without appreciably removing any of the metal the
niello is inlayed into. Obviously, if you've only got 1/100th of an
inch to spare, you'd need to know how not to obliterate the pattern.
And mercury (a.k.a. "fire gilding") can be applied thicker than this.
Now a second scenario, albeit briefly. Are you able to establish
with certainty that the gilding was fire gilded? Is it possible the
gold is actually inlayed into the niello? Certainly possible by
physical means using the right niello alloy and very high karat gold.
What is the base metal of the article? Many ancient craftspeople knew
that gold would bond at very low heat if it were close to pure and
the metal article was silver with a purified surface of fine silver.
Consider the Keum Boo technique often discussed here on Orchid.
Finally, there is an applique technique for mechanically binding gold
to other metals that doesn't use heat at all, such as the Japanese
used in their work. Again, without seeing the article I am only
David L. Huffman