An Eye under the Rust?

In my last Vindolanda expedition I did not find much fascinating stuff.  Luck of the draw sometimes, I was in interesting areas but the the artifacts were elsewhere.  I was reduced to furrowing my brow over twisty nails and odd bits of rusted lumps.  Surely this was "something" back in Roman times?

One item I featured was an "unidentified metal bit".

Mostly iron one supposes, but a couple of enigmatic flecks of grey peeking through.

When perusing the excellent site on the Binchester excavations I came across this photo, with the similar looking object being identified as a "seal box".  Could my artifact have been one?

The shape and size seem about right.  Oh, this is the bottom, which always has three holes in it.  The fancier upper part looks like this:

I confess that seal boxes were an artifact type I was not familiar with. This is a site dealing with seal boxes found in the U.K.  The artifact from Binchester, and perhaps (?) my mystery lump, would be of the "vesica" or eye shaped variety.

Here is an image from the above link, a nicely done summary of the known/unknown aspects of seal boxes by Colin J. Andrews.

I am certainly indulging in a little "off season" speculation here.  But note the central dimple in both of the images above.  It does appear to have an analog in my encrusted specimen.....

It is worth noting that seal boxes are a rather atypical find in late Roman sites, but that various types of brooches are common.  This would not be a common style, but until the lab soaks the crud free this remains a possibility.  Or it could be something else altogether...at the time there was speculation that it might be a small knife blade.