Siderazot

Chemical formula: Fe₃N₁.₃₃

Siderazot is a rare iron nitride, found in volcanic exhalation products, forming small, hexagonal crystals with a metallic luster.

## Characteristics Siderazot is a naturally occurring iron nitride that forms under specific volcanic conditions. It appears as very small, hexagonal, tabular or prismatic crystals, rarely exceeding 0.1 mm. It is usually observed as coatings and aggregates on lava or in fumaroles. Due to the size of the crystals, its macroscopic features are difficult to assess without magnification. ## Physical Properties This mineral is characterized by a metallic luster. It is opaque. Its hardness and density have not been precisely measured due to the small size of the crystals and its rarity, but the density calculated based on the formula and cell parameters is approximately 6.63 g/cm³. ## Colors and Varieties Siderazot ranges in color from reddish-brown to black. No varieties have been distinguished. ## History and Name The name siderazot comes from the Greek words *sideros* (iron) and *azoton* (nitrogen), directly referring to its chemical composition. The mineral was first described by the Italian mineralogist Arcangelo Scacchi in 1876 based on material found in products of the 1872 Vesuvius eruption. Its status as a distinct mineral species was questioned for years but was finally confirmed and approved by the IMA in 1962. ## Uses Siderazot has no industrial applications. It is solely an object of scientific and collecting interest for specialized micromineral collectors.

Properties

Color: White, silver-white
Luster: Metallic
Streak: Black
Density: 3.147
Cleavage: Imperfect on {0001}
Fracture: Uneven
Transparency: Opaque
Crystal system: Hexagonal

Diagnostic features

## Identification Identifying siderazot under amateur conditions is practically impossible. It requires specialized equipment, such as an electron microscope with an EDS analyzer or an X-ray diffractometer (XRD), to confirm its chemical composition and crystal structure. A preliminary indication may be the occurrence of small, hexagonal, metallic crystals in volcanic exhalation products. ## Distinguishing from Similar Minerals It can be confused with other small, dark minerals from fumaroles, such as hematite or magnetite. Differentiation relies solely on advanced analytical methods. The crystal shape (hexagonal) can be a helpful feature but is not sufficient for certain identification. ## Crystal Forms Siderazot forms very small, hexagonal, tabular or short-prismatic crystals. They usually occur as single, scattered crystals or small aggregates on the surface of lava.

Geological environment

## Genesis Siderazot is a mineral of volcanic origin. It forms as a result of the reaction of nitrogen-rich volcanic gases with iron-containing aerosols at high temperatures, in the environment of fumaroles and volcanic exhalations. It crystallizes directly from the gas phase on the surface of cooling lava. ## Mineral Associations This mineral co-occurs with other products of volcanic sublimation, such as hematite, magnetite, halite, sylvine, and alkali metal and ammonium chlorides. ## Localities The most important and classic occurrence of siderazot is the Vesuvius-Somma volcanic complex in Italy, from which the type material originates. It has also been reported in products of the Etna volcano eruption in Sicily.

Rarity

Very rare

For collectors

## Quality Criteria As a micromineral, siderazot is primarily valued for the quality and size of its crystals, although these rarely reach significant dimensions. The most desirable specimens are those with well-formed, sharp, hexagonal crystals, clearly contrasting with the substrate. The abundance of crystals on the rock matrix also increases its collector's value. ## Popular Localities The only source of collector specimens of historical and reference importance is Vesuvius in Italy. Specimens from this volcano are the standard for this mineral.

Care and storage

## Cleaning Siderazot specimens are extremely small and delicate, often occurring as coatings on other rock material. Mechanical cleaning is not recommended. If necessary, compressed air (from a safe distance) can be used to remove dust. Avoid contact with water and chemicals. ## What to Avoid Moisture, acids, and all chemical solvents that may react with nitrides or the surrounding material should be absolutely avoided. Specimens are susceptible to mechanical damage due to their small size. ## Storage It is recommended to store specimens in specialized micromount boxes, in a dry environment, away from dust and direct light sources. The box protects delicate crystals from physical damage and contamination.

External references

https://www.mindat.org/min-3646.html