Minasragrite

Chemical formula: V⁴⁺O(S⁶⁺O₄)·5H₂O

Minasragrite is a very rare, hydrated vanadyl sulfate, forming characteristic, vivid blue coatings and aggregates.

## Characteristics Minasragrite is a hydrated vanadyl sulfate, most commonly occurring as microcrystalline aggregates, coatings, or spherical masses. It rarely forms small, tabular or prismatic crystals. Its most distinctive feature is its intense, vivid color, which makes it easily noticeable despite its small size. ## Physical Properties This mineral is very soft, with a Mohs hardness of only 1-2, meaning it can be scratched with a fingernail. It is also very light, with a density of approximately 2.03 g/cm³. It exhibits a vitreous luster and is translucent. It is soluble in water. ## Colors and Varieties Minasragrite occurs in shades from vivid, cobalt blue to lighter, aquamarine blue. It retains its blue color in transmitted light as well. No commercial or color varieties are distinguished. ## History and Name The mineral was first described in 1915 by Waldemar T. Schaller. Its name comes from its discovery locality – the Ragra mine (formerly known as Minas Ragra) in the Huayllay district, Pasco province, Peru. This is the only confirmed occurrence of this mineral in the world. ## Uses Due to its extreme rarity and small size of occurrences, minasragrite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and for scientific institutions.

Properties

Mohs hardness
1-2
Luster
Vitreous
Density
2.03
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification The key diagnostic features of minasragrite are its vivid, cobalt-blue color, very low hardness (1-2 on the Mohs scale), and occurrence in the form of coatings and microcrystalline aggregates. Its solubility in water is also a characteristic feature. ## Distinguishing from Similar Minerals Minasragrite can be confused with other secondary, blue vanadium or copper minerals. It differs from chalcanthite by the absence of a sweet taste and a slightly different shade. Distinguishing it from other rare vanadium sulfates (e.g., stanleyite) requires advanced chemical (EDS) or X-ray (XRD) analyses for unambiguous identification. ## Crystal Forms It most commonly forms granular or earthy coatings and crusts. It also occurs as spherical aggregates. Small, tabular crystals with a monoclinic habit are rarely observed.

Geological environment

## Genesis Minasragrite is a secondary mineral, forming in the oxidation zone of vanadium deposits. It forms as a result of weathering and alteration of patronite, a vanadium sulfide (VS₄), under the influence of surface waters. It is a post-sylvine product, meaning it crystallizes from aqueous solutions under low temperature and pressure conditions. ## Mineral Associations This mineral co-occurs with other vanadium minerals, mainly patronite (as the primary mineral), as well as other secondary vanadium sulfates. In its type locality, it is also associated with native sulfur and quartz. ## Localities The only confirmed and described occurrence of minasragrite in the world is its type locality: the Ragra mine in the Huayllay district, Pasco region, Peru.

Rarity

Very rare

For collectors

## Quality Criteria The most highly valued minasragrite specimens are those that show the largest possible surface covered with a vivid, intensely blue coating. The presence of even microscopic, well-formed crystals significantly increases the value of the specimen. Contrast with the host rock matrix is also important. Due to the nature of the mineral, clarity and transparency are not key criteria. ## Popular Localities The only source of minasragrite specimens is the Ragra mine in Peru. All samples available on the collector's market come from this single locality.

Care and storage

## Cleaning Minasragrite specimens are extremely delicate and soluble in water. They should absolutely not be cleaned wet. Only very careful dust removal with a soft brush or a stream of compressed air from a distance is permissible. ## What to Avoid Avoid contact with water and any chemicals, which will immediately damage it. The mineral is very soft, so it must be protected from any physical contact and scratching. As a hydrated mineral, it is sensitive to changes in humidity and temperature, which can lead to its dehydration and disintegration. ## Storage Specimens should be stored in stable conditions, preferably in a sealed, closed "micromount" box, which will protect them from mechanical damage, dust, and humidity fluctuations. Avoid exposure to direct sunlight and keep away from heat sources.

External references

Sources

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