Eritrina Punta de lanza
Eritrina is a mineral with formula Co₃(AsO₄)₂·8H₂O, in the Arseniatos group. This specimen comes from Agoudal, Bou Azzer, Ouarzazate, Drâa-Tafilalet, Marruecos.
Description
Triangular micaceous fuchsia crystals. A central 7 mm spearhead-shaped crystal stands out.
History of this specimen
When I had this piece in hand I knew at once it could not be kämmererite, or clinochlore, as the seller claimed. The crystallisation was completely different. After researching, I confirmed it was an erythrite from Agoudal. With it I learned that erythrite can also crystallise as shown here: in spearheads or perfect rhombs. It is also an exceptional piece: the contrast with the black-metallic matrix sets off intact crystals, free of chips or fractures, and a principal crystal of unusual size that is a pleasure to study under the loupe. It came from an earlier collection from the 1970s and, given the quality, it is very likely to have belonged to the stock of the old dealer Gary Hansen. A delightful piece and a fortunate purchase.
About Eritrina
Known as "flore de cobalt" (cobalt bloom), it is the fuchsia counterpart of vivianite—a hydrated cobalt arsenate. It arises from skutterudite's exposure to oxygen, and its color ranges from pale pink to intense fuchsia depending on cobalt concentration. In Agoudal, it forms flat, pointed crystals with a silky luster and deep wine color, frequently confused with roselite or anorthoroselite. For miners, erythrite on the surface confirmed that a cobalt, nickel, or silver deposit lay directly beneath it.
About the locality
In the Bou Azzer district, and especially at Agoudal, erythrites occur in cavities within altered Co–Ni arsenides, with scorodite and quartz. The mine is noted for producing specimens with exceptionally saturated colour and a compact matrix, denser than in other parts of the district.
Technical data
- Catalogue No.
- 0213
- Composition
- Co₃(AsO₄)₂·8H₂O
- Name
- Eritrina
- Variety
- Punta de lanza
- Group
- Arseniatos
- Category
- Cavella
- Matrix
- Matriz arseniatada
- Mine
- Agoudal
- District / Municipality
- Bou Azzer
- Province
- Ouarzazate
- Region
- Drâa-Tafilalet
- Country
- Marruecos
- Size (cm)
- 6 x 4 x 3
- Etymology
- From the Greek "erythros", 'red', for its characteristic colour.
- Quality
- Top
- Value trend
- Al alza
Related specimens
- Goethita (Botroidal) — Marruecos
- Malaquita (Fibrosa) — Marruecos
- Vanadinita — Marruecos
- Eritrina (Acicular) — Marruecos
- Pirolusita (Pseudomorfa parcial tras manganita) — Marruecos
- Malaquita (Pseudomorfa tras Azurita) — Marruecos
- Vanadinita — Marruecos
- Vanadinita — Marruecos