Hammered Charles I Silver Groat. Charles I Silver Groat, Aberystwyth, Wales. Aberystwyth mint, 1.95 grams, approx. 21 mm, mintmark Book, struck 1638-42. S 2893 Brooker 771. In 1637 a mint was set up in Aberystwyth, to make silver coins with silver from Welsh mines. Dies were supplied from the Tower […]