Uramphite
Chemical formula: N<sup>3-</sup>H<sub>4</sub>(U<sup>6+</sup>O<sub>2</sub>)PO<sub>4</sub>·3H<sub>2</sub>O
Uramphite is a rare, secondary uranium mineral with a characteristic yellow-green color and radioactivity, occurring in the oxidation zones of uranium deposits.
Properties
- Mohs hardness
- 2.5
- Luster
- Vitreous, Pearly
- Streak
- Light yellow
- Density
- 3.65
- Cleavage
- Perfect on {001}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Tetragonal
Diagnostic features
## Identification The key diagnostic feature of uramphite is its strong radioactivity, detectable with a Geiger counter. Its characteristic light yellow to yellow-green color and occurrence in the form of small, tabular crystals forming rosetted aggregates are also distinctive. Under shortwave and longwave ultraviolet radiation, it exhibits strong, bright green fluorescence. ## Distinguishing from Similar Minerals Uramphite can be confused with other secondary uranium minerals of similar color, such as meta-autunite, saleeite, or torbernite. Differentiation often requires advanced analytical methods, such as chemical analysis (EDS) to confirm the presence of phosphorus and the absence of calcium (unlike autunite) or copper (unlike torbernite). The presence of the ammonium ion is unique to uramphite in this group. ## Crystal Forms Crystals are very small, thin-tabular, with a square or rectangular outline. They most often form radial or rosetted aggregates, as well as thin coatings and crusts on the host rock.
Geological environment
## Genesis Uramphite is a secondary mineral, formed in the oxidation zones of hydrothermal uranium deposits. It forms as a result of phosphate-rich solutions acting on primary uranium minerals, in an environment rich in ammonium compounds, which can originate from the decomposition of organic matter in sedimentary rocks. ## Mineral Associations This mineral co-occurs with other secondary uranium minerals, such as uraninite (pitchblende), meta-autunite, phosphuranylite, as well as with quartz, kaolinite, and iron hydroxides (limonite). ## Localities The most important and well-documented occurrences of uramphite worldwide include the uranium mine in Příbram, Czech Republic, and the Strelcovskoye deposit on the Vitim Plateau in Siberia, Russia. It has also been reported at the White King mine in Lake County, Oregon, USA.
Rarity
Very rare
For collectors
## Quality Criteria Specimens with well-formed, distinct rosetted aggregates of intense, yellow-green color, contrasting with the dark host rock, are most valued by collectors. Due to the microscopic size of the crystals, the size and richness of the aggregates on the matrix are important. Specimens from classic, well-documented localities, such as Příbram, are more highly prized. ## Popular Localities Specimens from Příbram, Czech Republic, which have yielded some of the highest quality crystals of this mineral, are among the most sought after by collectors.
Care and storage
## Cleaning Uramphite specimens should generally not be wet cleaned. Only gentle dust removal with a soft brush or compressed air from a safe distance is permissible. ## What to Avoid Contact with water, which can dissolve or damage the delicate crystals, must be strictly avoided. The mineral is sensitive to chemicals, high temperatures, and direct sunlight, which can cause fading and dehydration. As a radioactive mineral, it requires special precautions - avoid inhaling dust and direct skin contact. Wash hands thoroughly after each contact. ## Storage Uramphite specimens must be stored in sealed, lead-lined or thick plastic containers with clear radioactivity labeling. They should be kept away from other radiation-sensitive minerals, and also away from areas of permanent human habitation, especially bedrooms and living rooms.