Obverse:

IACOBVS D G MAG BRI FRA ET HI REX. Crowned bust r. with value mark XII behind.

Reverse:

QVÆ DEVS CONIVNXIT NEMO SEPARET. Large shield.

Graffiti 'X' on reverse otherwise very fine and toned. The rose is by far the scarcest mintmark of the third period coinage. Notably, it is only with this mintmark that the busts of James I are seen breaking the inner circle, a distinct departure from conventional die engraving that also appears later during the reign of Charles I. Oddie obverse die O3, the reverse not listed. 

Ex Baldwin's

For further reading see:

G. Oddie (2022) 'A Die Study of James I Shillings – Third Issue, Sixth Bust, mm Rose' British Numismatic Society Research Blog, https://britnumsoc.blog/2022/06/26/a-die-study-of-james-i-shillings-third-issue-sixth-bust-mm-rose-gary-oddie/