The Hemiobol denomination
An ancient Greek silver coin denomination with a value of 1/2 obol, or 1/12 drachm. Generally it weighs around 0,36 grams.

In Ptolemaic egypt, it was also struck in bronze.
Hemiobol

(1) Abdera 475-448 BC
Obverse: forepart of gryffin left
Reverse: scallop shell within insuce square
Ref: May 198-9; SNG Copenhagen 319
(2) Argilos c. 495-460 BC
Obverse: forepart of Pegasos right
Reverse: quadripartite incuse square
Ref: Liampi, Argilos period VI, 122-127;...
(3) Elaia 450-400 BC
Obverse: Helmeted head of Athena left
Reverse: E-Λ-A-I, olive wreath within incuse square
Ref: None provided
(4) Halikarnassos c. 400-340 BC
Obverse: head of ram right
Reverse: head of young male right, ?
Ref: SNG Helsinki 873; SNG Kayhan 996, S...
(5) Kolone 500-300 BC
Obverse: head of Athena right wearing Corinthian helmet
Reverse: star ornament within incuse square
Ref: Cf. Gorny & Mosch 176, 1246; Peus 4...
(6) Kolophon 450-410 BC
Obverse: head of Apollo facing
Reverse: incuse square; HM
Ref: Milne, Colophon 3; SNG Kayhan 355; ...
(7) Kyme 480-450 BC
Obverse: head of eagle left, KY
Reverse: quadripartite incuse square
Ref: SNG Cop 31; Klein 333.
(8) Kyme 480-450 BC
Obverse: head of eagle left; KY
Reverse: quadripartite incuse square
Ref: SNG Cop 31; Klein 333. (hemiobol)
(9) Kyzikos 480-450 BC
Obverse: Forepart of boar running left, upward tuna behind
Reverse: Head of roaring lion left within incuse square, star in upper left field
Ref: SNG France 375
(10) Kyzikos 450-400 BC
Obverse: forepart of boar left; tuna fish right
Reverse: head of lion left; star above
Ref: SNG Kayhan 57 ff.; SNG BnF 375; SNG...
(11) Lesbos 500-450 BC
Obverse: confronting boar heads, creating the illusion of a facing head of a panther
Reverse: incuse square punch
Ref: BMC Lesbos p152,18
(12) Soloi 430-390 BC
Obverse: helmeted head of Athena or Amazon left
Reverse: grape
Ref: SNG France 154-157
(13) Thasos c. 463-411 BC
Obverse: dolphin left; ••
Reverse: quadripartite incuse square
Ref: Le Rider 10; SNG Cop -; BMC 23 var ...
(14) Thraco-Macedonian c. 500-450 BC
AR Hemiobol Thrace | Macedonia
Obverse: Head of ram right
Reverse: Kantharos within incuse square
Ref: Tzamalis 50.