Hanawaltite
Chemical formula: Hg¹⁺₆Hg²⁺O₃Cl₂
Hanawaltite is a rare mercury mineral that forms dark, metallic-lustered crystals and coatings.
Properties
- Mohs hardness
- 4
- Luster
- Metallic
- Streak
- Dark reddish black
- Density
- 0
- Cleavage
- <mi>{001}</mi> good
- Fracture
- Irregular/Uneven
- Transparency
- Translucent,Opaque
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Identification of hanawaltite requires advanced laboratory methods, such as chemical composition analysis (EDS) and X-ray diffraction (XRD). Preliminary identification in a collection is based on its black color, strong metallic luster, dark reddish-black streak, and co-occurrence with other rare mercury minerals from the type locality. ## Distinguishing from Similar Minerals Hanawaltite can be confused with other black, metallic mercury minerals, such as eglestonite or terlinguaite, with which it often co-occurs. Definitive distinction is possible almost exclusively based on chemical and crystallographic analysis. ## Crystal Forms It forms very small, thin, tabular crystals, which typically arrange into rosette-like or random aggregates. It also occurs as thin coatings and crusts on the host rock.
Geological environment
## Genesis Hanawaltite is a secondary mineral, formed in the oxidation zones of mercury deposits. It forms as a result of low-temperature hydrothermal processes in a chlorine- and oxygen-rich environment, which react with earlier mercury minerals. ## Mineral Associations It co-occurs with other mercury minerals, such as cinnabar, native mercury, calomel, eglestonite, terlinguaite, wattersite, poyarkovite, and hanawaltite. These minerals form a characteristic mineralogical assemblage at the type locality. ## Localities The only confirmed occurrence of hanawaltite in the world is its type locality – the Clear Creek outcrop on Goat Mountain, in San Benito County, California, USA.
Rarity
Extremely rare
For collectors
## Quality Criteria For collectors, the most important aspect is the identification of the mineral, confirmed by analytical methods. The value of a specimen depends on the abundance of hanawaltite on the rock matrix and its association with other well-formed, rare mercury minerals. Due to the microscopic size of the crystals, their individual form is of lesser importance. ## Popular Localities The only source of hanawaltite specimens is its type locality in California, USA. This area is known for the occurrence of many rare and unique mercury minerals.
Care and storage
## Cleaning Due to its toxicity and fragility, cleaning is not recommended. If necessary, compressed air can be used to remove dust. Avoid contact with water and chemicals. ## What to Avoid Direct skin contact must be strictly avoided due to its mercury content. The mineral is sensitive to acids and other chemical reagents. It should be protected from high temperatures and humidity. ## Storage Hanawaltite specimens must be stored in sealed, clearly labeled containers, away from other minerals, to prevent contamination. It is recommended to keep it in a place inaccessible to children and pets, in a dry and stable environment.