Rakovanite

Chemical formula: (N³⁻H₄)₃Na₃[V⁵⁺₁₀O₂₈]·₁₂H₂O

Rakovanite is a very rare, water-soluble ammonium-sodium vanadate, forming orange, acicular crystals.

## Characteristics Rakovanite is a hydrated ammonium-sodium vanadate belonging to the decavanadate group. It occurs as very small, delicate, acicular or bladed crystals, which typically form radial aggregates, rosettes, or crusts. Individual crystals rarely exceed 1 mm in length. Due to its fragility and water solubility, it is an extremely difficult mineral to preserve in collections. ## Physical Properties Rakovanite crystals are flexible and pliable. This mineral is characterized by low hardness, estimated at approximately 1.5 on the Mohs scale, and low density. It is transparent to translucent, with a vitreous to silky luster. One of its most unusual features is its complete solubility in water. ## Colors and Varieties Rakovanite occurs in a uniform, characteristic, light-orange color. No color or commercial varieties are known. ## History and Name The mineral was discovered in the Sunday uranium mine in San Juan County, Utah, USA. It was described in 2008 by Anthony R. Kampf, Joe Marty, John M. Hughes, and Stuart J. Mills. The name "rakovanite" honors John Rakovan, Professor of Mineralogy at Miami University in Ohio (USA), for his contributions to mineralogy and geochemistry research. ## Uses Rakovanite has no industrial application. Its significance is purely scientific and as a collector's item, although due to its instability, it is a great rarity in collections.

Properties

Mohs hardness: 1
Color: Orange
Luster: Vitreous
Streak: Orange-yellow
Density: 2.407
Cleavage: Perfect on {010}
Fracture: Conchoidal
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Key diagnostic features of rakovanite are its orange color, habit of small, acicular crystals forming radial aggregates, and complete solubility in water. The reaction to water is an immediate and definitive test, though destructive to the sample. ## Distinguishing from Similar Minerals Minerals with similar color and habit include other secondary vanadates, such as carnotite or tyuyamunite, but none of them are water-soluble. Pascoite is also an orange, water-soluble vanadate, but it crystallizes in the monoclinic system and has a different chemical composition (it is a calcium vanadate). ## Crystal Forms Rakovanite forms elongated, acicular or bladed crystals, flattened parallel to {010} and elongated along [001]. Most often, they occur as radial or stellate aggregates and rosettes, as well as delicate crusts on the host rock.

Geological environment

## Genesis Rakovanite is a secondary mineral, forming in the oxidation zone of uranium-vanadium deposits in sedimentary rocks (sandstones). It forms in desert conditions as a result of post-mining processes, likely through the evaporation of solutions rich in vanadium, sodium, and ammonia. Ammonia may originate from the decomposition of organic matter contained in the host rock. ## Mineral Associations This mineral co-occurs with other secondary uranium and vanadium minerals. At the type locality (Sunday mine), it was found in association with gypsum, as well as on montroseite and near other unidentified vanadium minerals. ## Localities The only confirmed occurrence of rakovanite in the world is its type locality – the Sunday mine, in the Slick Rock district, San Juan County, Utah, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria The most highly prized rakovanite specimens are those with rich, well-formed, and undamaged radial aggregates on a small rock matrix. The intensity of the orange color and the size and completeness of the crystal rosettes significantly increase the specimen's value. Due to its extreme rarity, any specimen, even microscopic, is considered valuable. ## Popular Localities The only source of rakovanite specimens is the Sunday mine in Utah, USA. Material from this locality is extremely rarely available on the collector's market.

Care and storage

## Cleaning The mineral must under no circumstances be cleaned wet, as it is completely soluble in water. Any contact with water, even in the form of vapor, leads to its destruction. Mechanical cleaning is also inadvisable due to the extreme delicacy of the crystals. ## What to Avoid Water, moisture, high humidity, chemicals, and ultrasound should be avoided. Specimens must be protected from temperature changes that could cause water vapor condensation. It should not be touched, as moisture from the skin can damage it. ## Storage Rakovanite requires storage in an hermetically sealed container, preferably with a desiccant (e.g., silica gel). It should be displayed away from light and heat sources, in stable room conditions. The safest form of storage is a sealed "perky box" type container.