You seem to have managed to get a (flash?) reflection right over the mark. It would be better without the reflection and lit by daylight at an angle to bring out any features better.
However, assuming that it is IC (and it does look somewhat like that) then I have a candidate mark which I have seen with hallmark dates 1792 to 1801:
One of my seen-on items for this IC is a mustard. Unfortunately the mark doesn't appear in any of the standard references so is "unknown".
Phil