Philoxenite
Chemical formula: (K,Na,Pb<sup>2+</sup>)<sub>4</sub>(Na,Ca)<sub>2</sub>(Mg,Cu<sup>2+</sup>)<sub>3</sub>(Fe<sup>3+</sup><sub>0.5</sub>Al<sub>0.5</sub>)(S<sup>6+</sup>O<sub>4</sub>)<sub>8</sub>
Phylloxenite is a rare sulfate with a complex chemical composition, forming small, tabular crystals of an intensely green color.
Properties
- Mohs hardness
- 3
- Luster
- Vitreous
- Streak
- Pale green
- Density
- 3.55
- Cleavage
- Perfect on {0001}
- Fracture
- Brittle
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
Diagnostic features
## Identification Identification of phylloxenite is based on its characteristic emerald-green color, specific crystal form (small, tabular plates), and typical occurrence in volcanic fumaroles. Due to its microscopic size, final confirmation requires advanced analytical methods, such as Raman spectroscopy or chemical analysis (EDS). ## Distinguishing from Similar Minerals Phylloxenite can be confused with other green minerals found in similar environments, such as atacamite, paratacamite, or some arsenates. Distinguishing it from these minerals "by eye" is practically impossible and requires laboratory analysis. However, the form of thin, tabular crystals is quite characteristic. ## Crystal Forms Phylloxenite crystallizes as very thin, tabular crystals with hexagonal or octagonal outlines. These crystals often combine into radial or rosette-like aggregates, and also form thin coatings and crusts on the surface of the host rock.
Geological environment
## Genesis Phylloxenite is a mineral of volcanic origin, formed by sublimation from volcanic gases in high-temperature fumaroles. It crystallizes directly from hot vapors rich in sulfur and metals at temperatures of approximately 400-450°C. ## Mineral Associations This mineral co-occurs with other sulfates and oxides typical of fumarolic environments. The most common associated minerals include: hematite, tenorite, anglesite, chalcanthite, langbeinite, aphthitalite, euchlorine, dolerophanite, and wulfenite. ## Localities The only confirmed locality of phylloxenite in the world (type locality) is the "Yadovitaya" fumarole within the second cinder cone, formed during the northern eruption of the Great Fissure of Tolbachik volcano in Kamchatka, Russia.
Rarity
Very rare
For collectors
## Quality Criteria The collecting appeal of phylloxenite specimens primarily depends on the richness and aesthetics of the crystal aggregates. The most prized specimens are those with clearly formed, undamaged crystals creating dense, rosette-like clusters of an intense green color. Contrast with the light host rock is also important. Due to the microscopic nature of the mineral, all specimens are micromounts. ## Popular Localities The only source of phylloxenite specimens is its type locality – Tolbachik volcano in Kamchatka, Russia. All specimens available on the collector's market originate from this single location.
Care and storage
## Cleaning Phylloxenite specimens, which are usually micromounts, should not be cleaned mechanically or chemically. If necessary, dust can be removed very carefully using a photographic air blower or a stream of compressed air from a distance. ## What to Avoid Avoid contact with all chemicals, including acids and bases. The mineral is brittle and susceptible to mechanical damage, so avoid vibrations, impacts, and sudden temperature changes. It should not be washed with water or ultrasonically. ## Storage Specimens should be stored exclusively in specialized micromount boxes to protect them from dust, moisture, and physical damage. Storage under stable room conditions is entirely sufficient.