Pliny’s Natural History treats orichalcum among copper-alloy and legendary metal speech neighboring brass. A named orichalcum in that encyclopedia, not brass as the copper-zinc neighbor already walked and not electrum as gold–silver alloy.
Pausanias names orichalcum as the metal of an inscribed heart whose lettering he discusses among Greek sanctuary antiquities. A named orichalcum in that periegesis, not brass as the copper-zinc neighbor already walked under Pliny and not bronze under a fancy name.