Hayelasdiite
Chemical formula: [Pb<sup>2+</sup><sub>4</sub>O<sub>1.5</sub>(OH)<sub>2.5</sub>]<sub>2</sub>[Cu<sup>1+</sup><sub>5</sub>(S<sup>6+</sup>O<sub>3</sub>S<sup>2-</sup>)<sub>4</sub>(S<sup>6+</sup>O<sub>3</sub>S<sup>2-</sup>H)<sub>2</sub>(H<sub>2</sub>O)]·4H<sub>2</sub>O
Hayelasdiite is an extremely rare, newly discovered copper and lead sulfate-sulfide mineral, distinguished by its unique crystal structure and intense blue color.
Properties
- Mohs hardness
- 2
- Luster
- Vitreous
- Streak
- Light blue
- Density
- 4.45
- Cleavage
- Perfect on {0001}
- Fracture
- Uneven
- Transparency
- Transparent
- Crystal system
- Trigonal
Diagnostic features
## Identification Identification of the mineral is based on its characteristic, intensely blue color, the form of small tabular crystals forming rosette-like aggregates, and its occurrence in association with other rare secondary minerals from the Blue Bell mine. Identification requires advanced analytical techniques, such as Raman spectroscopy or X-ray diffraction. ## Distinguishing from Similar Minerals It may be confused with other blue secondary copper minerals, such as linarite, azurite, or cyanotrichite. Differentiation is possible based on chemical analysis (presence of thiosulfates) and crystallography. In field conditions or without specialized equipment, differentiation is practically impossible. ## Crystal Forms It forms thin, tabular crystals with a hexagonal outline, which combine into rosette-like or spherulitic aggregates. Individual crystals are rare.
Geological environment
## Genesis Hayelasdiite is a secondary mineral that formed as a result of oxidation processes in the weathering zone of a polymetallic deposit. It crystallizes in voids within quartz rock, in an environment rich in copper, lead, and sulfur, under low-temperature conditions. ## Mineral Associations This mineral co-occurs with other rare secondary minerals, such as anglesite, linarite, chalcanthite, brochantite, cerussite, hemimorphite, as well as newly described species like castellaroite and zanazziite. ## Localities The only confirmed occurrence of Hayelasdiite in the world is its type locality – the Blue Bell mine in San Bernardino County, California, USA. This is a historic copper, silver, and lead mine known for the occurrence of many rare secondary minerals.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of a Hayelasdiite specimen depends on the intensity and purity of its blue color, the size and definition of the crystal aggregates, and the richness of its occurrence on the rock matrix. Specimens with clearly formed, rosette-like crystal clusters, contrasting with the light host rock, are most valued. The presence of other rare associated minerals also increases the specimen's value. ## Popular Localities The only source of Hayelasdiite specimens is the Blue Bell mine in California, USA. All specimens available on the collector's market originate from this single location.
Care and storage
## Cleaning Due to the extreme delicacy and small size of the crystals, mechanical cleaning is not recommended. Specimens should be protected from dust by storing them in sealed containers. If cleaning is absolutely necessary, compressed air can be used from a safe distance. ## What to Avoid Avoid contact with water, chemicals, acids, and detergents. The mineral is likely sensitive to changes in temperature and humidity. It should not be exposed to direct sunlight, which may cause its degradation. ## Storage Hayelasdiite specimens should only be stored in specialized, sealed "micromount" boxes, protecting them from dust, moisture, and mechanical damage. It is best to store them under stable room conditions.