JFD32AN7: The habit of this Pyrite is known in Spain as a 'matchbox'. Some faces of the cube are wider and more elongated than the others, giving this 'rectangular' appearance. They are rare in Navajún and when they do appear they are highly desired, especially if they are in matrix, as in this case.
Ampliación a Victoria Mine, De Alcarama Range, Navajún, Comarca Cervera, La Rioja  Spain (2014)

Specimen size: 6.4 × 5.1 × 3.7 cm = 2.52” × 2.01” × 1.46”

Main crystal size: 2.7 × 2.3 cm = 1.06” × 0.91”