Shilovite

Chemical formula: Cu²⁺(N³⁻H₃)₄(N⁵⁺O₃)₂

Shilovite is a rare, water-soluble copper and ammonium nitrate, forming dark blue, tabular crystals.

## Characteristics Shilovite is a very rare mineral from the nitrate group, being a complex copper and ammonium nitrate. It forms small, tabular or bladed crystals, usually not exceeding 1 mm in length. Its most characteristic feature is its intense, dark blue color. It is a secondary mineral, forming under specific conditions on mine dumps. ## Physical Properties Shilovite crystals exhibit a vitreous luster. This mineral is very soft and brittle. One of its key properties is complete water solubility, which makes it unstable in a humid environment. ## Colors and Varieties Shilovite occurs in a uniform, dark blue color. No color varieties or commercial varieties are known. ## History and Name The mineral was discovered on a burning mine dump of the "Anna" coal mine in Alsdorf, Germany. It was described and approved as a new mineral species by the International Mineralogical Association (IMA) in 2013 (IMA2013-067). Its name honors the Russian chemist Aleksandr E. Shilov (1930-2014), known for his research on C-H bond activation and nitrogen reduction. ## Uses Due to its extreme rarity, small crystal size, and instability, shilovite has no practical application. It is solely an object of scientific and collecting interest for specialized collectors.

Properties

Mohs hardness
2
Color
Deep violet blue
Luster
Vitreous
Streak
violet blue and becomes light blue as a result of decomposition and loss of NH3
Density
1.92
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Key diagnostic features of shilovite are its intensely dark blue color, tabular crystal habit, and complete water solubility. It occurs in a very specific environment – on burnt mine dumps. ## Distinguishing from Similar Minerals It can be confused with other blue secondary copper minerals, such as chalcanthite or azurite. Chalcanthite is also water-soluble but forms crystals of a different habit (short prismatic) and crystallizes in the triclinic system. Azurite is harder, does not dissolve in water, and reacts vigorously with acids, unlike shilovite. ## Crystal Forms Shilovite forms thin, tabular or bladed crystals, often grouped into small aggregates or rosettes. Crystals are usually very small, less than 1 millimeter in length.

Geological environment

## Genesis Shilovite is a mineral of anthropogenic origin. It forms as a sublimation product resulting from the reaction of gases (ammonia and nitrogen oxides) on burning coal mine dumps. These gases react with copper present in the gangue, crystallizing in cooler zones as small efflorescences. ## Mineral Associations At the type locality (Anna mine), it co-occurs with other rare secondary minerals such as salammoniac, challacolloite, kremersite, kladnoite, and hematite. ## Localities The only confirmed occurrence of shilovite in the world is its type locality – the dump of the former "Anna" coal mine in Alsdorf, in the Aachen region, North Rhine-Westphalia, Germany.

Rarity

Extremely rare

For collectors

## Quality Criteria The collector's appeal of a shilovite specimen primarily depends on the size and development of the crystals. Specimens with distinct, sharp tabular crystals forming aesthetic groups on a contrasting matrix are most valued. Due to the microscopic size of the crystals, specimens are mainly evaluated under magnification. The purity and intensity of the blue color also affect the value. ## Popular Localities The only source of shilovite specimens is its type locality in Alsdorf, Germany. All specimens available on the collector's market originate from this single location.

Care and storage

## Cleaning The mineral **must not be cleaned** with water or any other liquids, as it is completely soluble in them. Only very careful removal of dust with a soft brush or a stream of dry air is permissible. ## What to Avoid Contact with water, water vapor, and high air humidity must be strictly avoided, as these lead to its dissolution. It must be protected from all chemicals, acids, and cleaning agents. It is very soft and brittle, so any physical contact and vibrations should be avoided. ## Storage Shilovite specimens must be stored in hermetically sealed containers (e.g., "perky box" type) or in specialized display cases with humidity control. Storage with moisture-absorbing substances (e.g., silica gel) is highly recommended. It should be kept away from heat sources and direct sunlight.

External references

Sources

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