The Tetartemorion denomination
A tetartemorion is an ancient Greek denomination worth 1/4 obols, and weighing 0.18 grammes.

The name comes from 'tetarton', meaning a fourth, and 'morion' meaning part - a "quarter-part".
Tetartemorion

(1) Caria | Mylasa? 420-390 BC
Obverse: forepart of lion right
Reverse: pigeon left, pellet above and below
Ref: SNG Kayhan 947
(2) Kolophon 520-500 BC
Obverse: head of Apollo right
Reverse: incuse square
Ref: SNG von Aulock 1810 var(head right)...
(3) Kyme 480-450 BC
Obverse: head of eagle left; KY
Reverse: quadripartite incuse square
Ref: SNG Cop 31; Klein 333. (hemiobol)
(4) Phokaia | Teos 521-478 BC
Obverse: head of griffin left
Reverse: incuse square
Ref: Cf. Hirsch 221, lot 331, BMC 88-89
(5) Teos 475-450 BC
Obverse: seated griffin right, rising leg
Reverse: quadrate incuse square
Ref: SNG Kayhan 601