A novelty of 2014 for Spanish mineralogy (see: La extraordinaria paragénesis de minerales de mercurio de Usagre )
Group of Eglestonite crystals—a mineral species produced by the alteration of other mercury minerals—with dominant octahedral forms, on matrix, honey-colored, translucent, and completely filling a vug, as well as being dispersed throughout the rest of the piece. They are accompanied by Calomel crystals with an adamantine luster and small Mercury droplets that are sustained thanks to their high surface tension.
Both mercury halide species have been analyzed.
These minerals are photosensitive, blackening easily in sunlight and even under lamp light, so we recommend keeping them in the dark.
The Mariquita mining group is a group of cinnabar concessions comprising Mariquita (7800), Ampliación a Mariquita (9251), Gran Canaria (10703), 2ª Gran Canaria (10752), 3ª Gran Canaria (10785), and Ana María (11198), and is located in the southern sector of Badajoz Province, within a domain dominated by Paleozoic rocks affected by fracturing and hydrothermal fluid circulation. Mineralization corresponds to a mercury deposit, developed along fracture zones and brecciated areas, where oxidation and supergene alteration processes have generated a paragenesis rich in halides, oxides, and secondary Hg species, including uncommon phases of high mineralogical interest.
Mariquita mining group, Cerro de las Minas, Usagre, Comarca Campiña Sur, Badajoz, Extremadura Spain (2015)
Specimen size: 3.2 × 2.7 × 1.3 cm = 1.26” × 1.06” × 0.51”
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