NFD52XXX: Specimen of Donharrisite, a very rare nickel and mercury sulfide of considerable size for the species, formed by very bright black tabular crystals on a Quartz matrix. A mineral species present in only three countries and that in Spain also occurs at the Eugenia Mine, Bellmunt del Priorat.
It has been published in the magazine ‘Paragénesis’ number 01/2025, page 115.
Furthermore, this specimen has been mentioned in thread FMF - MineralExpo Barcelona-Sants 2024 (edición octubre) - Minerales Invisibles

The locality is part of the historic Almadén–Almadenejos mining district, one of the most important in the world for mercury. The mineralization is dominated by Cinnabar, with the presence of other species, some of them very uncommon, and is associated with a hydrothermal system developed mainly in Paleozoic materials, with slate and quartzite host rocks. These processes gave rise to mercury deposits of great continuity and historical relevance, exploited since Roman times and playing a key role in European and worldwide mining.
El Entredicho Mine, Almadenejos, Comarca Valle de Alcudia, Ciudad Real, Castilla-La Mancha  Spain (08/09/2023)

Specimen size: 5 × 3.2 × 2.1 cm = 1.97” × 1.26” × 0.83”

Main crystal size: 0.5 × 0.2 cm = 0.20” × 0.08”