Autunita
Autunita is a mineral with formula Ca(UO₂)₂(PO₄)₂·10–12H₂O, in the Fosfatos group. This specimen comes from Schneeberg, Schneeberg, Erzgebirgskreis, Sajonia, Alemania and joined the Terrium collection in 1900.
Description
Aggregate of yellow, waxy autunite on earthy massive quartz matrix. The coating is confined to a defined zone, with fine lamellar development and subdued lustre.
History of this specimen
Specimen with an old German label "Kalkuranit auf Quarz. Schneeberg". I can reasonably place it between the late 19th century and the first decades of the 20th (c. 1890–1930) from a combination of features: pen‑and‑ink handwriting, including the hand‑drawn border; aged paper with homogeneous oxidation; use of classical German collection nomenclature ("auf Quarz", "Schneeberg"); and, significantly, the use of the historical term "Kalkuranit", prior to the modern standardisation of species such as autunite. This set of elements matches central European mineralogical labels prior to the generalisation of typewritten formats from the mid‑20th century. The seller also indicated that the piece comes from the Bergakademie Freiberg, in Saxony, within a group of old specimens he obtained from that source. In 19th‑century Freiberg, mineralogy teaching encouraged the creation of personal collections. Exchanges among students from across Europe produced holdings of great richness and variety that still endure. Scholarship holders and distinguished students from different parts of Europe also converged there, and many of those collections ended up being especially rich in provenances and species.
About Autunita
Autunite is a hydrated uranyl-calcium phosphate. In classical collections it was one of the species that made uranium visible: compared with primary minerals such as UO2, dark and compact, here uranium appears in lamellar, crustose or scaly forms, yellow to yellow‑green in colour, far more legible to the eye of the collector and the mineralogist. It therefore played a central role in European mineralogy of the 19th and 20th centuries, both in the study of uranium alteration and in the formation of old academic collections. It is also unstable in the cabinet on a historical timescale: it readily loses water and can pass to metautunite, so many old specimens changed appearance or label over time. That mix of fragile beauty, scientific importance and shifting nomenclature explains its weight within classical uranium collecting.
About the locality
Schneeberg is a major Saxon classic and one of the European uranium classics. It lies in a historic district of polymetallic hydrothermal veins with silver, bismuth, cobalt, nickel and uranium, worked since the 15th century. Numerous secondary uranium minerals formed in its oxidised zones on quartz gangue, among them autunite. The locality also carries exceptional historical weight for the so‑called "Schneeberg disease": a high incidence of pulmonary illness among miners documented already in the 16th–17th centuries, today interpreted as one of the earliest recognised cases of lung cancer associated with prolonged exposure to radon and uranium decay products in underground mines.
Technical data
- Catalogue No.
- 0286
- Composition
- Ca(UO₂)₂(PO₄)₂·10–12H₂O
- Name
- Autunita
- Group
- Fosfatos
- Category
- Núcleus Ardens
- Matrix
- cuarzo
- Mine
- Schneeberg
- District / Municipality
- Schneeberg
- Province
- Erzgebirgskreis
- Region
- Sajonia
- Country
- Alemania
- Acquired
- 1900
- Etymology
- From the place name Autun, in Burgundy (France), a historic locality associated with the species.
- Quality
- Buena
- Value trend
- Estable