The Tritartemorion denomination
The tritartemorion was an ancient greek coin denomination worth 3 tartemoria - and weighing roughly 0.54 grammes.

The name comes from 'tetarton', meaning a fourth, and 'morion' meaning part. So it is literally a 'three-quarters-part'.
Tritartemorion

(1) Mende c. 460-423 BC
Obverse: ass standing right
Reverse: crow standing right within incuse square
Ref: SNG ANS 354
(2) Thasos 411-404 BC
Obverse: head of Satyr left
Reverse: two dolphins - upper to the left, lower to the right; ΘAΣI
Ref: SNG Cop 1033-1034; Le Rider 12; HGC...