NFG88AQ0: A novelty for Spanish mineralogy (see: La extraordinaria paragénesis de minerales de mercurio de Usagre)
Crystals of Calomel with an adamantine luster, some of them clearly dominant and easily visible, and with Eglestonite crystals, a mineral species, product of alteration of other mercury minerals, an element that is also present in the specimen as small drops of native Mercury that hold together thanks to their high surface tension. The quality of this sample is exceptional, compared to other specimens from the same discovery. Both of the mercury halide species have been analyzed and we will send a copy of the analysis to the buyer.
These minerals are photosensitive, blackening easily when exposed to sunlight and even under the light of a lamp, so we recommend keeping them out of the reach of light.
This specimen has been photographed and published as a novelty at the 2023 Sainte Marie Show in the magazine ‘Lapis‘ number 7-8/2023, page 66
Mariquita mining group, Cerro de las Minas, Usagre, Comarca Campiña Sur, Badajoz, Extremadura  Spain (2015)

Specimen size: 6.7 × 3.7 × 2.4 cm = 2.64” × 1.46” × 0.94”