Obverse - Second crowned bust in ruff left, class II, bust 2a, crown 3a, no inner circles, value X in field behind, Latin legend and outer beaded border surrounding, initial mark castle (1627-28) both sides. The abbreviated obverse legend translates as "Charles, by the Grace of God, King of Great Britain, France and Ireland" and on the reverse "God protects His worshippers."

Reverse - Crowned quartered shield of arms, Latin legend without stops and outer beaded border surrounding.

Weight 4.41g

The original pyx trial records show that a total of £234,915 of crown gold was struck under the mint mark castle at full weight from 27th April 1627 until 3rd July 1628.