Inaglyite
Chemical formula: Pb²⁺Cu²⁺₃Ir³⁺₈S²⁻₁₆
Inaglyite is an extremely rare lead, copper, and iridium sulfide, forming microscopic, hexagonal crystals with a metallic luster.
Properties
- Mohs hardness
- 5.5
- Color
- Steel gray
- Luster
- Metallic
- Streak
- Black
- Density
- 0
- Cleavage
- In two directions
- Transparency
- Opaque
- Crystal system
- Hexagonal
Diagnostic features
## Identification Identification of inaglyite is impossible without advanced laboratory equipment. It requires chemical composition analysis using an electron microprobe (EDS/WDS) and X-ray diffraction (XRD) studies to confirm its crystal structure. In reflected light under a ore microscope, it is gray and exhibits weak anisotropy. ## Distinguishing from Similar Minerals It can be confused with other rare platinum-group metal sulfides, such as cuproiridsite, malanite, or irarsite, with which it often co-occurs. Definitive differentiation is only possible based on precise chemical analysis, which will reveal the presence of lead in the inaglyite structure. ## Crystal Forms It forms small, tabular, hexagonal crystals, up to 0.2 mm in size. It occurs as single grains or inclusions in other minerals, mainly in chromitite.
Geological environment
## Genesis Inaglyite is a mineral of magmatic origin. It forms in ultrabasic, alkalized rock complexes, particularly in dunites and chromitites. Its crystallization is associated with processes occurring in platinum-group element-rich layered intrusions. ## Mineral Associations It most commonly co-occurs with chromite, cuproiridsite, irarsite, laurite, malanite, and native osmium, iridium, and platinum. ## Localities The only confirmed and thoroughly described occurrence (type locality) is the Inagli dunite massif, located on the Aldan Shield in Yakutia, Russia. Its occurrences have also been reported in the ophiolite complex in the Polar Urals (Russia).
Rarity
Extremely rare
For collectors
## Quality Criteria In the case of such a rare mineral, the only criterion is its confirmed presence in the sample. Collectible specimens are most often fragments of the host rock (chromitite) with microscopic inaglyite inclusions, identified analytically. The value of a specimen increases if it is accompanied by other rare platinum-group minerals, and if the inaglyite itself forms relatively "large" (on a micro scale) and well-formed crystals visible under a microscope.
Care and storage
## Cleaning Due to its extreme rarity and microscopic size, inaglyite specimens are not subjected to standard cleaning. Any cleaning attempts should only be undertaken in laboratory conditions by specialists, most often using compressed air or ultrasonics in an appropriate medium. ## What to Avoid Any contact with chemicals, acids, and sudden temperature changes should be avoided. Any mechanical intervention (e.g., attempting to scratch, touch) is absolutely inadvisable and risks destroying the microscopic specimen. ## Storage Specimens containing inaglyite should be stored in specialized, sealed "micromount" boxes, protecting them from dust, moisture, and shocks. It is best to keep them in stable room conditions, away from direct sunlight and heat sources.