Jarosita
Jarosita is a mineral with formula KFe₃(SO₄)₂(OH)₆, in the Sulfatos group. This specimen comes from Túnel del Arteal, Cuevas del Almanzora, Almería, Andalucía, España and joined the Terrium collection in 2025.
Description
Curved cavity lined with minute lustrous jarosite crystals, dark honey to olive-gold in colour, forming a dense, sparkling druse on reddish-brown earthy matrix. The piece has a strongly arched, almost organic silhouette that lends it marked character.
About Jarosita
It is the mineral of Mars. Jarosite is a secondary potassium iron sulphate, linked to oxidation processes in sulphide-rich mine environments. In other words, a supergene neoformation. Its significance went beyond terrestrial mineralogy when Opportunity detected it on Mars in 2004, confirming that liquid water had also existed there.
About the locality
Túnel del Arteal produced some of the most recognisable Spanish jarosites, noted for their dark ferruginous aspect and small geodes lined with microcrystals. Many pieces come from rather unattractive earthy masses, so when a well-defined cavity appears, with relief, continuous lustre and a good visual read, the result has much greater cabinet presence than its size suggests.
Technical data
- Catalogue No.
- 0609
- Internal reference
- X0314
- Composition
- KFe₃(SO₄)₂(OH)₆
- Name
- Jarosita
- Group
- Sulfatos
- Category
- Cavella
- Mine
- Túnel del Arteal
- District / Municipality
- Cuevas del Almanzora
- Province
- Almería
- Region
- Andalucía
- Country
- España
- Size (cm)
- 5 x 5 x 2
- Weight
- 50 g
- Acquired
- 2025
- Etymology
- Named for its type locality, Barranco del Jaroso (Almería, Spain).
- Quality
- Muy buena
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Aerenita — España
- Aerinita (fibrosa) — España
- Analcima — España
- Analcima — España