diameter on this coin is too large

i compared it to 1⁄25 Crown - Elizabeth II Pádraig Pearse, Gibraltar (2022) which according to numista is 11 mm and it is smaller, though quite a thick small coin, i think it is 10 mm diameter

you think it's 10mm? You need to take an accurate measurement if you are eyeballing a difference of only 1mm. 

Use a pair of digital calipers if you have any. Photos are also required. 

Also please tell us why you linked the ¼ sovereign, as you did not mention it and the size info on it is correct.

i don't have a callipers, you can eyeball 1mm, eyes can resolve down to about 50 um for most people, it is noticeably smaller anyway. the 1/25 crown coin shows up as the smallest in my collection, but it is not true i don't think as this quarter sov in my collection is smaler, unless it pertains also to volume and/or density… was just letting you know anyway, it is not a huge issue. Thanks for your response

¼ sovs are meant to be 13.5mm which would mean it's meant to be bigger than the 1/25 crown, can you please post photos of your coins?

Thanks for your post. I just corrected the Pearse 1/25 crown - correct diameter 13.92mm, see here: https://www.dublinmintoffice.ie/popular-themes/seven-signatories/padraig-pearse-bu-gold-coin 

¼ crowns is OK with diameter 13.5mm

Many thanks MMowiec!

Most of the 0,5 gram gold coins are with diameter 11mm. This one (Pearce) has diameter 13,92 which is usually used for 1/25 crown weighted 1.24 gram, so it must be very very thin.

thanks for the additional info.. yes wafer thin, and very easy to bend! a smaller thicker coin would have been a better way to go