Autunita
Autunita is a mineral with formula Ca(UO₂)₂(PO₄)₂·10-12H₂O, in the Fosfatos group. This specimen comes from Mina Assunçao, Aldeia Nova, Ferreira de Aves, Viseu, Portugal and joined the Terrium collection in 2012.
Description
Group of autunite crystals on perfectly terminated quartz columns. Pronounced colour contrast. Under UV light the crystals show vivid green fluorescence.
History of this specimen
Collected by hand in 2012 by Antonino Bueno y Patiño at the Assunçao open-pit mine, Portugal. I protected it with Paraloid B-72.
About Autunita
Autunite is a uranium phosphate forming as a secondary mineral in oxidising environments. In this piece the autunite crystals are sharp and only slightly powdery, and they occur with well-crystallised quartz—an association uncommon at Assunçao. Fluorescent and radioactive, it is a Portuguese classic.
About the locality
From a disused open-pit mine in an area where finds depended on hand searching.
Technical data
- Catalogue No.
- 0137
- Composition
- Ca(UO₂)₂(PO₄)₂·10-12H₂O
- Name
- Autunita
- Group
- Fosfatos
- Category
- Núcleus Ardens
- Matrix
- Cuarzo
- Mine
- Mina Assunçao
- District / Municipality
- Aldeia Nova
- Province
- Ferreira de Aves
- Region
- Viseu
- Country
- Portugal
- Size (cm)
- 10 x 5.5 x 3.5
- Weight
- 210 g
- Acquired
- 2012
- Ex-collection
- Patiño
- Etymology
- From the French "Autun", referring to the city of Autun (France), near the type locality where it was first described.
- Quality
- Muy buena
- Value trend
- Estable