Plata Kongsbergita
Plata is a mineral with formula Ag(Hg), in the Elementos Nativos group. This specimen comes from Corta San Matilde, Herrerías, Almería, Andalucía, España and joined the Terrium collection in 2006.
Description
Very fresh silver ball, free of dark sulphidation, with very fine, almost frosted dendritic growth, forming a three-dimensional aggregate—not poor wires or fragments—with a clear "nest" habit. Extremely delicate.
History of this specimen
One of the two smaller sister kongsbergites from the same find as the large specimen now held by the Colegio de Minas. Juan, who found them, located them at Corta San Matilde when machinery was still working the open pit and he used weekends to explore on his own. He would go down to the bottom, pass through unstable zones and, to avoid falling, brace his back against the wall while pushing his arm into holes and cavities as far as his shoulder allowed. In one of those voids he felt the large "bird's nest" from which these pieces came. It was a Sunday afternoon and he had to extract it then: the next day he was back at school and the machinery could raze the area. Juan also recalled that these mineralisations appeared at the contact of the kongsbergites with barite, within marly ground packed with marine fossils.
About Plata
This silver typology from the Corta San Matilde stands out for its dendritic and arborescent development, characterized by its association with traces of mercury (a paragenesis that defines kongsbergites). Its genesis occurred within cavities of a marly matrix, originating from low-enthalpy (low-temperature) hydrothermal processes.
About the locality
Corta San Matilde, Las Herrerías, Almería: a modern open pit opened over a much older mining district. The geological setting preserves the imprint of an ancient compressed sea floor, visible in the fossiliferous marls of the area. Ancient submarine hydrothermal system channelled by faults, with later mineralisation in cavities associated with barite. The last activity in the area (Grupo Berja) was carried out by MINERSA (2006), extracting barite for the cement industry, insulation and other uses.
Technical data
- Catalogue No.
- 0369
- Composition
- Ag(Hg)
- Name
- Plata
- Variety
- Kongsbergita
- Group
- Elementos Nativos
- Category
- Cupidium
- Mine
- Corta San Matilde
- District / Municipality
- Herrerías
- Province
- Almería
- Region
- Andalucía
- Country
- España
- Size (cm)
- 3.5 x 2.5 x 2.2
- Weight
- 8.4 g
- Acquired
- 2006
- Ex-collection
- Juan Morillas López
- Etymology
- From the element uranium and the Greek "kirkos" ("falcon"), in honour of the type locality Falkenstein ("Falcon Stone") in Bavaria, Germany.
- Quality
- Notable
- Value trend
- Al alza
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