Perchukite-(Y)
Chemical formula: Pb²⁺YAs³⁺Si₂O₈
Perchukite-(Y) is an extremely rare lead, yttrium, arsenic, and silicon mineral, discovered in the Ilímaussaq complex in Greenland.
Properties
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identification of perchukite-(Y) is possible only through advanced laboratory methods, such as scanning electron microscopy (SEM) combined with chemical composition analysis (EDS/WDS) and electron backscatter diffraction (EBSD) to determine the crystal structure. Visual characteristics are insufficient for identification. ## Distinguishing from Similar Minerals This mineral occurs in paragenesis with many other rare minerals from Ilímaussaq. Distinguishing it from co-occurring silicates, arsenates, and sulfides is impossible without chemical analysis. ## Crystal Forms Observed exclusively as anhedral, microscopic grains that form small clusters (aggregates).
Geological environment
## Genesis Perchukite-(Y) forms under hydrothermal conditions within highly differentiated, alkaline nepheline syenite intrusions. Its occurrence is associated with pegmatites and ussingite veins cutting through host rocks, such as lujavrites. ## Mineral Associations This mineral co-occurs with many other rare species, which is typical for this type of locality. Its paragenesis includes, among others, ussingite, steenstrupine-(Ce), lueshite, sphalerite, vitusite-(Ce), vuonnemite, as well as newly discovered minerals like grenmarite and petersenite-(Y). ## Localities The only confirmed locality for perchukite-(Y) in the world is its type locality: an ussingite vein within the Ilímaussaq alkaline complex, Kujalleq, South Greenland.
Rarity
Extremely rare
For collectors
## Quality Criteria As a microscopic mineral, perchukite-(Y) is not evaluated according to typical collector criteria such as size, color, or crystal form. Its value is purely scientific and systematic. For collectors specializing in systematic minerals or from specific localities (so-called "locality collectors"), the only criterion is possessing an analytically confirmed specimen from the type locality. ## Popular Localities The only source of material is the Ilímaussaq complex in Greenland. Specimens are available exclusively in scientific circulation and among highly specialized rare mineral collectors.
Care and storage
## Cleaning Due to its microscopic nature and extreme rarity, specimens containing perchukite-(Y) should not be cleaned mechanically or chemically. Any intervention may destroy or dislodge the fine mineral grains. ## What to Avoid Avoid contact with any chemicals, ultrasound, as well as changes in temperature and humidity. The specimen should be treated as an archival object. ## Storage Store in stable conditions, preferably in a specialized "micromount" box, protecting against dust, shocks, and contamination. Avoid exposure to light, although there is no data on its effect on the mineral.