Novacekita
Novacekita is a mineral with formula Mg(UO₂)₂(AsO₄)₂·10–12H₂O, in the Arseniatos group. This specimen comes from Mina Cuervo, Sierra Gómez, Chihuahua, México and joined the Terrium collection in 2025.
Description
Micro-acicular novacekite encapsulated or encrusted within coralliform aragonite–gypsum–magnesium aggregates on a limonitic matrix. Strong white–ochre contrast and excellent relief; under longwave UV the aragonite shows very intense green fluorescence.
History of this specimen
Old collection piece with label "Novacekit xx 263 (MEX) – Sierra Matre Mountains" and a later one "Sierra Madre, California, USA". After checking references, I corrected the provenance to Sierra Gómez (Chihuahua, Mexico) and I keep both labels as documentation of the reassignment. I got the piece at auction well below its real value, a real bargain for such an aesthetic, complex and uncommon specimen.
About Novacekita
Hydrated magnesium uranyl arsenate, a member of the "autunite group"; tabular to acicular, radioactive and fluorescent. Typical of the oxidised zones of uranium deposits with secondary phases.
About the locality
Sierra Gómez is a classic locality for uranyl arsenates associated with aragonite and gypsum. Production was limited and specimens are sought for their aesthetics and fluorescence.
Technical data
- Catalogue No.
- 0113
- Composition
- Mg(UO₂)₂(AsO₄)₂·10–12H₂O
- Name
- Novacekita
- Group
- Arseniatos
- Category
- Núcleus Ardens
- Matrix
- Matriz limonítica
- Associations
- Aragonito Yeso
- Mine
- Mina Cuervo
- District / Municipality
- Sierra Gómez
- Province
- Chihuahua
- Country
- México
- Size (cm)
- 7.5 x 4.5 x 4
- Weight
- 82.4 g
- Acquired
- 2025
- Ex-collection
- Colección antigua (etiqueta nº 263)
- Etymology
- Named in 1951 by C. Frondel in honour of Radim Nováček (1905–1942), mineralogist and analytical chemist at Charles University in Prague; a member of the Czech resistance to the Nazi occupation, arrested in 1941 and executed at Mauthausen for treason; also linked to his colleague Karel Tuček ("tučekite"), whom he recruited to the resistance before his death.
- Quality
- Notable
- Value trend
- Al alza
Related specimens
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Adamita — México
- Adamita — México
- Adamita — México
- Adamita (Cuprífera) — Grecia
- Adamita — México