Pyracmonite

Chemical formula: (N₃-H₄)₃Fe₃+(S₆+O₄)₃

Pyrakmonite is a very rare ammonium-iron sulfate, forming microscopic, colorless crystals in volcanic environments.

## Characteristics Pyrakmonite is a hydrated ammonium iron sulfate. It occurs as very small, hexagonal, tabular crystals, typically not exceeding 50 micrometers. The crystals are colorless and transparent, with a vitreous luster. Due to its microscopic size, it is a mineral primarily accessible to advanced micromount collectors. ## Physical Properties Due to the extremely small size of the crystals, most physical properties of pyrakmonite, such as hardness, density, cleavage, or fracture, have not been precisely determined. The luster is described as vitreous, and the streak as white. ## Colors and Varieties This mineral is colorless. No colored varieties or commercial varieties are known. ## History and Name Pyrakmonite was discovered in the fumaroles of the La Fossa crater on Vulcano Island (Aeolian Islands, Italy). It was approved as a new mineral by the IMA in 2008. Its name comes from the Greek words *πῦρ* (pyr - fire) and *ἄκμων* (akmōn - anvil), which refers to Hephaestus (Roman Vulcan), the god of fire and smiths, whose forge, according to mythology, was located under Mount Etna. The name also refers to the mineral's volcanic origin. ## Uses Pyrakmonite has no industrial application. It is solely an object of scientific and collecting interest.

Properties

Luster: Vitreous
Streak: White
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of pyrakmonite is possible almost exclusively by advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), due to the microscopic size of the crystals. Visually, under high magnification, characteristic small, hexagonal, tabular crystals can be observed. ## Distinguishing from Similar Minerals Pyrakmonite co-occurs with other fumarolic sulfates such as mascagnite, sal ammoniac, and godovikovite. Distinguishing it from these minerals without specialized equipment is practically impossible. All form similar coatings and microscopic crystals in the same environment. ## Crystal Forms It forms small, tabular crystals with a hexagonal outline. They usually occur as single, scattered crystals or small aggregates on the surface of volcanic rock.

Geological environment

## Genesis Pyrakmonite is a mineral of volcanic origin. It forms by direct sublimation from volcanic gases (exhalations) in active fumaroles, at temperatures from 100 to 250°C. It crystallizes on the surface of volcanic rocks and ashes. ## Mineral Associations It most commonly co-occurs with other fumarolic minerals, such as sal ammoniac, mascagnite, godovikovite, and native sulfur. ## Localities The only confirmed and described locality of pyrakmonite in the world is its type locality - the active fumaroles of the La Fossa crater on Vulcano Island, part of the Aeolian Islands archipelago in Italy.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a pyrakmonite specimen is assessed based on the abundance and visibility of microcrystals on the matrix. The most prized specimens are those where the crystals, despite their microscopic size, are well-formed, have a distinct hexagonal outline, and are abundantly scattered over a small area. Contrast with the color of the host rock also enhances the visual appeal of the specimen under a microscope. ## Popular Localities The only source of pyrakmonite specimens is its discovery site - Vulcano volcano in Italy. All specimens available on the collector's market come from this single locality.

Care and storage

## Cleaning Pyrakmonite specimens are extremely delicate and usually occur as coatings or microcrystals on another mineral (matrix). Mechanical or chemical cleaning is not recommended. If necessary, compressed air can be used very carefully from a safe distance to remove loose dust. ## What to Avoid The mineral is water-soluble, so contact with water and other liquids must be strictly avoided. It should be protected from moisture, high temperatures, and all chemicals. Due to its delicacy, touching and vibrations should be avoided. ## Storage Specimens should be stored in a sealed, dry "micromount" container, preferably with a desiccant (e.g., silica gel). Store at a stable room temperature, away from direct sunlight.

Sources

IMA Mineral List (CNMNC)