Siderita
Siderita is a mineral with formula , in the Carbonatos group. This specimen comes from Túnel del Arteal, Cuevas del Almanzora, Almería, Andalucía, España and joined the Terrium collection in 2025.
Description
Rhombohedral siderite crystals in mustard and dark brown tones, raised on a grey matrix. Some with stepped growth and pearly lustre. The piece is triangular, and the crystals rise in a common orientation across the rock face, visually recalling a flock of birds at dusk. Good under a loupe.
History of this specimen
Sober piece with strong geological character. The piece has an entry on FMF: https://www.foro-minerales.com/forum/download.php?id=53996
About Siderita
Siderite is an iron carbonate common in hydrothermal environments, where it crystallises in rhombohedral forms. Its colour varies with impurities and the degree of oxidation. In this piece the oriented arrangement of the crystals and the natural texture of the matrix stand out.
About the locality
The Túnel del Arteal, in Cuevas del Almanzora, forms part of the Almería mining district, known for jarosites, siderites and other secondary species. Activity has been halted for years, but the area continues to yield pieces with an oxidised aesthetic and well-developed crystallisation.
Technical data
- Catalogue No.
- 0481
- Internal reference
- T0089
- Name
- Siderita
- Group
- Carbonatos
- Associations
- CaFe(CO₃)₂
- Mine
- Túnel del Arteal
- District / Municipality
- Cuevas del Almanzora
- Province
- Almería
- Region
- Andalucía
- Country
- España
- Size (cm)
- 12 x 7 x 5.5
- Weight
- 364 g
- Acquired
- 2025
- Etymology
- From the Greek "sideros" ("iron").
- Quality
- Buena
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Aerenita — España
- Aerinita (fibrosa) — España
- Analcima — España
- Analcima — España