The Trichalkon denomination
The trichalkon was an ancient Greek bronze denomination worth 3 chalkoi.

Since the numbe of chalkons to an obol varied across regions a general weight is impossible to define, except that it weighed three chalkoi from the region it was struck in..
Trichalkon

(1) Hadrian 119-120 AD
Obverse: laureate, draped and cuirassed bust right from behind; AYTO KAIC TPAIA__AΔPIANOC CEB
Reverse: veiled and turreted head of Tyche right; MHTPOΠOΛEωC__ANTIOXEωN THC / Γ
Ref: RPC III, 3728; BMC 302; CRS 261; Mc...
(2) Phokian Confederation 351-347 BC
Obverse: three filleted boukrania; ΦΩ_ΚΕ_ΩΝ
Reverse: laureate wreath; T
Ref: Slg. BCD Lokris - Phokis 328; SNG C...