Ermakovite
Chemical formula: (N<sup>3-</sup>H<sub>4</sub>)(As<sup>3+</sup><sub>2</sub>O<sub>3</sub>)<sub>2</sub>Br
Ermakovite is an extremely rare ammonium arsenite with bromine, forming colorless, prismatic crystals in volcanic exhalations.
Properties
- Luster
- Adamantine
- Streak
- White
- Density
- 3.93 (obliczona)
- Transparency
- Transparent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification The primary diagnostic feature is its occurrence environment – active volcanic fumaroles. It is distinguished by its form of small, colorless, prismatic crystals gathered in radial aggregates with an adamantine luster. Final identification is only possible using advanced analytical methods, such as X-ray diffraction (XRD) and chemical microanalysis (EDS). ## Distinguishing from Similar Minerals It can be confused with other colorless volcanic sublimates, such as arsenolite. However, arsenolite crystallizes in the isometric system, typically forming small octahedra, while ermakovite forms prismatic crystals in the orthorhombic system. Definitive differentiation requires laboratory analysis. ## Crystal Forms Crystals have a prismatic habit. They typically form radial, stellate, or spherulitic aggregates and thin crusts on volcanic rocks.
Geological environment
## Genesis Ermakovite is a product of sublimation from hot volcanic gases. It forms in active fumarole zones at temperatures of approximately 100-150°C, as a result of reactions between volcanic gas components rich in arsenic, ammonia, and bromine. ## Mineral Associations It co-occurs with other fumarolic minerals, such as arsenolite, realgar, and other rare arsenites and halides formed under similar conditions. ## Localities The only confirmed locality in the world is its type locality – the fumaroles of Avachinsky Volcano on the Kamchatka Peninsula, Russia.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of an ermakovite specimen is assessed based on the size and development of radial aggregates, as well as the abundance of the mineral on the rock matrix. Due to its extreme rarity, any specimen with well-defined crystals is considered valuable. An additional advantage is its association with other rare fumarolic minerals. ## Popular Localities Specimens originate exclusively from one location in the world – Avachinsky Volcano in Kamchatka, making them extremely difficult to acquire.
Care and storage
## Cleaning Cleaning the specimen is absolutely not recommended. The mineral is water-soluble and unstable in humid air. Any attempt at wet cleaning will lead to its destruction. ## What to Avoid Avoid contact with water, water vapor, and humid air. The mineral is highly toxic due to its arsenic content – avoid direct skin contact, inhaling dust, and always wash hands after any contact. Store away from heat and light sources. ## Storage Ermakovite specimens must be stored in sealed, airtight containers (e.g., "perky boxes"), preferably with a desiccant (silica gel). The container should be clearly labeled as "POISON".