JFD180AP1: One hell of a piece (for this deposit anyway). Chalcopyrite is not exactly the most famous species from the Troya mine, but this specimen, found in the first years of exploitation, shows good sharp crystals, displaying a nice contrast with the Dolomite and the Siderite that are typical there.
Of the best possible quality for this locality.
Troya Mine, Mutiloa, Comarca Goyerri, Guipúzcoa / Gipuzkoa, Basque Country (Euskadi)  Spain (±1983)

Specimen size: 12.3 × 8.9 × 3.4 cm = 4.84” × 3.50” × 1.34”

Main crystal size: 1.6 × 1.2 cm = 0.63” × 0.47”