Nováčekite
A phosphate mineral and member of the Autunite group, Nováčekite is a radioactive uranium mineral.
It typically forms as a secondary mineral in the oxidised zone of uranium polymetal deposits.
Information about Nováčekite
Nováčekite is a rare magnesium uranium arsenate mineral belonging to the autunite group, forming small but brightly coloured yellow platy crystals in the oxidised zones of uranium deposits. It is primarily of scientific interest, collected for its vivid colour, its strong fluorescence, and perhaps for some collectors, the remarkable and sobering story behind the man it honours.
It typically occurs as thin square to rectangular platy crystals, sometimes aggregated into fan-like or rosette groups, and is typically bright canary-yellow to pale yellow in colour, with a vitreous to pearly lustre. Individual crystals are translucent to transparent and rarely exceed 1-2 mm. In the field, the vivid yellow colour and strong fluorescence under ultraviolet light are the most immediately striking features.
Nováčekite forms in the oxidised, near-surface zones of uranium-bearing hydrothermal polymetallic deposits, where magnesium and arsenic are available in the surrounding groundwater alongside the uranium derived from the breakdown of primary uranium minerals such as uraninite.
It is the arsenate analogue of saleeite, in which arsenate is replaced by phosphate, and belongs to the autunite group alongside uranocircite, torbernite, and related uranium minerals. It is closely related to metanováčekite, a dehydrated form that develops as nováčekite loses water – a process that is reversible under ambient conditions, meaning specimens can cycle between the two forms depending on humidity.
A note on nomenclature: The naming history of nováčekite is unusually complex. The mineral was first described in 1951 as novacekite. In 1964 Kurt Walenta established two differently hydrated forms – nováčekite-I (12 water molecules, the more hydrated species, now renamed hydronováčekite) and nováčekite-II (10 water molecules). Diacritical marks were added to the name in 2008. In 2022 the IMA formally renamed the species from nováčekite-II to simply nováčekite, and nováčekite-I to hydronováčekite. Older collection labels, dealer descriptions, and literature references may use any of these names. Most specimens encountered in collections are the 10-water-molecule species – nováčekite as currently defined – as hydronováčekite rapidly dehydrates to nováčekite on exposure to normal atmospheric conditions.
Uses and History
Nováčekite has no industrial or gemological applications. It is collected as a scientific and aesthetic specimen, valued for its colour and fluorescence, and for the exceptionally significant figure in whose honour it was named.
The mineral was first described in 1951 by the American mineralogist Clifford Frondel, from specimens collected in connection with uranium mineralogy research. It was named in honour of Radim Nováček (21 March 1905 – 12 February 1942), mineralogist and analytical chemist at Charles University in Prague – one of the most distinguished mineralogists of his generation in central Europe, who had made important contributions to the study of uranium mineralogy and arsenate minerals before his death at the age of 36.
Nováček’s story is one of the more extraordinary and tragic in the history of mineralogy. Following the Nazi occupation of Czechoslovakia, the Czech intelligentsia came under systematic persecution. Nováček became involved in resistance intelligence operations from 1939, and also recruited his fellow mineralogist Karel Tuček – after whom tučekite is named – to the resistance. He was arrested in October 1941, convicted of treason against the Nazi occupying authority, and transferred to the Mauthausen concentration camp in Austria, where he was executed on 12 February 1942. He was 36 years old. The naming of a uranium mineral in his honour by Frondel in 1951 was a deliberate act of memorial, and nováčekite carries that history in its name.
Notable localities include the Clara Mine at Oberwolfach in the Black Forest, Germany, which has produced some of the finest specimens; Schneeberg in Saxony, Germany, a historically important uranium mining district; the Wittichen district in the Black Forest; the Rabejac Mine in the Lodève uranium district of Hérault in southern France; the Pedra Preta pit in Brazil; and Cuervo Mine in Mexico.
Mineralogy
Hazards and Warnings
Radioactive and toxic mineral: contains uranium and arsenic.
Nováčekite is highly radioactive and must be handled and stored accordingly. Collectors should wash their hands thoroughly after handling, avoid inhaling any dust, and never place specimens near the mouth. Specimens should be stored away from areas of prolonged human occupation – a sealed display case in a well-ventilated room, at some distance from where people spend extended time, is recommended. Specimens must be kept completely out of reach of children.
The radiation level of individual specimens varies and depends on the size and uranium content of the material. For general guidance on the safe handling and storage of radioactive minerals, the Geological Curators Group has published freely available advice that collectors may find useful.
Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis. When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.
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- Nováčekita
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- Nováčekite
- Novacekite (without diacritics)
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- Nováčekite
Russian:
- Новачекит
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- Nováčekite
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- Nováčekit
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