Zircarsite
Chemical formula: Na₁₈Cu²⁺₁₂Zr⁴⁺O₈(As⁵⁺O₄)₈Cl₆
Zircarsite is an extremely rare copper and zirconium arsenate, forming microscopic, tabular crystals of an intense green color.
Properties
- Luster
- Vitreous
- Streak
- Green
- Cleavage
- Perfect on {0001}
- Transparency
- Transparent to translucent
- Crystal system
- Isometric
Diagnostic features
## Identification Field identification of Zircarsite is impossible due to its microscopic size. Identification requires advanced laboratory techniques, such as chemical analysis (EDS) and X-ray structural analysis (XRD). In a collection, under a microscope, it can be preliminarily identified based on its characteristic emerald-green color, tabular crystal habit, and radial aggregates, as well as its locality (Tolbachik volcano). ## Distinguishing from Similar Minerals At the type locality (Tolbachik), many other green copper arsenates occur, such as eriochalcite, lammerite, and euchroite. Distinguishing Zircarsite from these minerals is only possible through chemical analysis, which will show the presence of zirconium – an element not found in other similar minerals from this locality. ## Crystal Forms Zircarsite forms very small, thin, tabular crystals with hexagonal or rectangular outlines. These crystals often combine into radial or rosette-like aggregates, and also form thin crusts and coatings.
Geological environment
## Genesis Zircarsite is a fumarolic mineral. It forms by sublimation from hot volcanic gases in exhalation zones, at temperatures of approximately 150-250°C. It crystallizes directly on the surface of volcanic rocks, such as basalt. ## Mineral Associations This mineral coexists with other rare fumarolic minerals, such as hematite, tenorite, arsenowinogradowite, lammerite, eriochalcite, euchroite, alexite, and sylvite. ## Localities The only confirmed occurrence of Zircarsite in the world is its type locality – Arsenatnaya fumarole, located on the second cinder cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption (1975-1976) on Tolbachik volcano, Kamchatka, Russia.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of Zircarsite specimens is primarily assessed based on the richness and aesthetics of the crystal aggregates visible under a microscope. Most valued are specimens with clearly formed, radial or rosette-like crystal clusters of an intense green color, contrasting well with the host rock. The size of individual crystals, although always microscopic, also affects the value of the specimen. ## Popular Localities The only source of Zircarsite specimens is its type locality at Tolbachik volcano in Kamchatka. All specimens available on the collector's market originate from this single location.
Care and storage
## Cleaning Zircarsite specimens are extremely delicate and small, therefore they should not be cleaned mechanically or chemically. Any attempts at cleaning risk irreversible damage or loss of the microscopic crystals. It is best to leave them in their untouched state. ## What to Avoid Avoid contact with any chemicals, including acids and bases. The mineral is likely sensitive to changes in temperature and humidity. It should be protected from ultrasound, vibrations, and direct physical contact. ## Storage Specimens should be stored exclusively in specialized "micromount" boxes, which protect them from dust, shocks, and mechanical damage. Display should be away from sources of vibration and direct sunlight.