A 300 AD 'Pax Christi' medallion

[Roerbakmix]

I was cleaning up my ever growing pile of uncleaned AE and AR Roman, Celtic and miscellaneous coins, to sell a bunch of them online in order to create budget. These coins come from metal detectorists in The Netherlands - I keep the rarer ones and those in good condition, and at intervals sell the uncleaned encrusted ones online. One object caught my attention: a small, probably lead 'blob' of metal, about 10x7 mm. At first I discarded it, thinking it would be a piece of molten lead. But then I noted the small hole: at least someone, at some moment, pierced it. Upon closer inspection, I noted it had been scratched purposely: a large P and X on one side (the Pax Christi simbol), and an X on the other side: 

In hand, the symbol is clearer. 

The artifact was part of a group lot of Roman and Celtic ae (dated between 100 BC and 400 AD), found in the Southern of the Netherlands (Limburg). Someone, probably between 1600 and 2000 years ago, took a small piece of molten lead (?), engraved a PX symbol on the flat side and a cross on the other side, and then pierced it in order to wear it. And subsequently, he lost it. 

A cool find, almost discarded. I gifted it to my sister, who intends to wear it.