You’ve finally got some scales 😃
Taking your weight, and using the criterion from the North article below, I’d say yours is an early issue (1280-1284?) Dublin farthing - Open Es & Cs and the clear wedge-tailed R of Rex.
Whilst the reverse legend is weak, it does appear to me that there are both a D and an I starting in each quarter, making it Dublin (CIVI TAS DVBL INIE). I believe the only other mint for these farthings is Waterford (CIVI TAS VATE RFOR), so you can probably rule that out in this case…I’ll let you to decide what letters you see, it’ll be so much easier for you to confirm in-hand.
https://www.britnumsoc.org/publications/Digital BNJ/pdfs/1997_BNJ_67_4.pdf