Charles I. Civil War, AR Shilling, Diamond-shaped siege money of Newark. 1645-1646. 27 mm, 5.42 g. Dated 1645. 

Crown; C R flanking, XII (value mark) below.
OBS NEWARKE 1645 in three lines. 

Seaby 3142; Brooker 1224; North 2640.

With permission of cngcoins.com, auction Triton XXII, lot 1427.