The Triobol denomination — Variants: Hemidrachm -
The Hemidrachm was an ancient Greek coin denomination with a value of 3 obols, which is half a drachm. it is also often called a triobol.

The hemidrachm generally weighs around 2.15 grams when struck in silver, but was also struck in bronze.
Hemidrachm|Triobol
(1) Argos
/Files/Images/Coinsite/CoinDB/Argosxx.jpg
An AR Triobol struck 125-80 BC in Argos
Obverse: forepart of dog

Reverse: big A, trident below; Δ _ A / MAP

Diameter: 15 mm
Die Orientation: -
Weight: 2.03 g
No notes for this coin
BCD Peloponnesos 1145; SNG Copenhagen 47-8
(2) Cherronesos
/Files/Images/Coinsite/CoinDB/cher.jpg
An AR Hemidrachm | Triobol struck 386 - 338 BC in Cherronesos (Thrace)
Obverse: Forepart of lion right, head reverted

Reverse: Quadripartite incuse square with alternating raised and sunken quarters; pellet in one sunken quarter, wreath in the opposite

Diameter: 13 mm
Die Orientation: -
Weight: 2.09 g
No notes for this coin
McClean 4076-7; HGC 3, 1437
(3) Kroton
/Files/Images/Coinsite/CoinDB/Kroton2.jpg
An AR Triobol struck c. 430-420 BC in Kroton
Obverse: Pegasos left; Ϙ

Reverse: Tripod with 3 ring handles and legs ending in lion’s paws; ϘPO

Diameter: 11 mm
Die Orientation: -
Weight: 1.5 g
Kroton had the rather curious practice of issuing fractions bearing reverse types taken from the coinage of other cities: such as, among others, the Pegasus of Corinth (complete with the letter koppa below), the hare of Messana and the octopus of Syracuse.
HN Italy 2127, SNG Cop 1788
(4) Lokri Opuntii
/Files/Images/Coinsite/CoinDB/Lokri_Opunti.jpg
An AR Triobol struck c. 340-330 BC in Lokri Opunti
Obverse: Head of Persephone right wearing wreath of grain, single-pendant earring, and pearl necklace

Reverse: Ajax the Lesser (son of Oileus) nude but for crested Corinthian helmet advancing right in fighting attitude holding short sword and shield on left arm ornamented inside with coiled snake (control symbol), helmet crest below; OΠONTIΩN

Diameter: 15 mm
Die Orientation: -
Weight: 2.7 g
No notes for this coin
SNG Cop.51, de Nanteuil 886, BCD Lokris-Phokis 96
/Files/Images/Coinsite/CoinDB/Phokis.jpg
An AR Triobol struck c. 440-420 BC in Daulis?
Obverse: facing bull head

Reverse: head of Artemis right; Φ O K I

Diameter: 13 mm
Die Orientation: -
Weight: 2.9 g
No notes for this coin
SNG Cop 99 ff.
/Files/Images/Coinsite/CoinDB/Obv_and_Rev_Sixth_Edit(2).jpg
An AE Triobol struck 246-222 BC in Alexandria
Obverse: Diademed and horned head of Zeus-Ammon right

Reverse: ΠΤΟΛΕΜΑΙΟΥ ΒΑΣΙΛΕΩΣ, eagle standing left on thunderbolt, wings closed; XP monogram between legs, filleted cornucopiae in left field

Diameter: 34 mm
Die Orientation: 11 H
Weight: 35.59 g
No notes for this coin
CPE B396; Svoronos 965; SNG Copenhagen 173-5
/Files/Images/Coinsite/CoinDB/01447q00.jpg
An AE Triobol struck 246-222 BCE in Alexandria
Obverse: Diademed head of Zeus Ammon to right, with ram's horn in his hair and over the diadem

Reverse: BAΣIΛEΩΣ ΠTOΛEMAIOY Eagle with closed wings standing left on thunderbolt; to left, filleted cornucopiae; between eagle's legs, monogram of X and P

Diameter: 36 mm
Die Orientation: 11 H
Weight: 38.15 g
No notes for this coin
CPE B396. SNG Copenhagen 173-5. Svoronos 965
/Files/Images/Coinsite/CoinDB/Auction_Pic_(Obv_and_Rev)_REDUCED(7).jpg
An AE Hemidrachm | Triobol struck c. 219 BC in Alexandria
Obverse: Diademed and horned head of Zeus-Ammon right

Reverse: ΠΤΟΛΕMAIOY ΒΑΣΙΛΕΩΣ, eagle standing left on thunderbolt; filleted cornucopia to left, ΔI between legs

Diameter: 34 mm
Die Orientation: 11 H
Weight: 36.46 g
Roma Numismatics E-Sale 64; Lot 446; Ex. Photographer’s Collection; Ex. Münzen und Medaillen GmbH (DE) Auction 17; Lot 1100; Acquired in 1970 from Münzen und Medaillen AG (Basel)
CPE B496; Svoronos 1127
/Files/Images/Coinsite/CoinDB/Ptolemy_VIII_(Obv_and_Rev).jpg
An AE Hemidrachm | Triobol struck 163-145 BC in Cyrene
Obverse: Diademed head of Zeus-Ammon right

Reverse: BAΣIΛEΩΣ ΠTOΛEMAIOY EYEPΓETOY, eagle standing right on thunderbolt, wings spread; Φ to right

Diameter: 44 mm
Die Orientation: 11 H
Weight: 38.36 g
No notes for this coin
SNG Copenhagen 651; Svoronos 1641
(10) Rhodos
/Files/Images/Coinsite/CoinDB/Rhodos.jpg
An AR Triobol struck 170-150 BC in Rhodos
Obverse: Radiate head of Helios facing slightly right

Reverse: APTEMΩN / P-O, rose with bud to right, hook to left; all within incuse square.

Diameter: 13.1 mm
Die Orientation: 11 H
Weight: 1.16 g
"Plinthophoricï" coinage. Artemon, magistrate. 
Jenkins 50; SNG Helsinki 658. VF
(11) Sikyon
/Files/Images/Coinsite/CoinDB/212.jpg
An AR Triobol struck an unknown year in Sikyon
Obverse: Dove flying left

Reverse: M Monogram

Diameter: 11 mm
Die Orientation: -
Weight: 2.1 g
SIKYONIA, Sikyon
SNG Copenhagen 103