Edoylerite

Chemical formula: Hg²⁺₃(Cr⁶⁺O₄)S²⁻₂

Edoylerite is an extremely rare mercury chromate sulfate, forming microscopic, yellow crystals with a strong, adamantine luster.

## Characteristics Edoylerite is a mineral from the sulfide group, containing mercury chromate. It occurs as very small, tabular or prismatic crystals, rarely exceeding 0.5 mm in length. It typically forms isolated crystals, groups of crystals, or thin coatings on the host rock. It is transparent to translucent, and its most characteristic features are its intense yellow color and exceptionally strong, almost adamantine luster. ## Physical Properties This mineral is very soft, with a Mohs hardness of approximately 2. It is also very dense, which is typical for mercury minerals. Luster is one of its most distinguishing features – described as adamantine to metallic. Due to the microscopic size of the crystals, many physical properties are difficult to measure precisely. ## Colors and Varieties Edoylerite occurs in a characteristic bright yellow to golden yellow color. No color varieties or commercial varieties are known. ## History and Name The mineral was discovered in the Socrates mercury mine in Sonoma County, California, USA. It was described and approved as a new mineral species by the International Mineralogical Association (IMA) in 1990. Its name honors Edward H. Doyler (born 1926), an American geologist who first found samples of this mineral and recognized it as a potentially new species. ## Uses Edoylerite has no industrial applications. Its significance is purely scientific and collectible, being a coveted item for specialized collectors of rare minerals.

Properties

Mohs hardness: 2
Color: Canary yellow to orangish yellow
Luster: Adamantine to Submetallic
Streak: Yellow
Density: 0
Cleavage: Good {010}. Fair {101}.
Fracture: Sub-Conchoidal
Transparency: Transparent,Translucent,Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Key diagnostic features of edoylerite include its intense yellow color, very strong adamantine luster, high density, and occurrence as microscopic, tabular crystals. Its origin from mercury deposits is also characteristic. ## Distinguishing from Similar Minerals Edoylerite can be confused with other secondary yellow mercury minerals, such as terlinguaite or eglestonite, which often co-occur with it. Differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). Its exceptionally strong luster can be a helpful visual clue. ## Crystal Forms Edoylerite crystals are usually very small, tabular, flattened parallel to {010}, or short prismatic. They often form small, loose aggregates or grow on other minerals.

Geological environment

## Genesis Edoylerite is a secondary mineral formed in the oxidation zones of hydrothermal mercury deposits. It forms as a result of weathering and alteration of primary mercury sulfides (mainly cinnabar) in the presence of chromium-rich solutions. Its formation is associated with serpentinites, which can be a source of chromium. ## Mineral Associations This mineral co-occurs with other secondary mercury minerals. In its type locality (Socrates mine), it was found in association with cinnabar, native mercury, edgarbaileyite, wattersite, gypsum, and minerals from the montmorillonite group. ## Localities The only confirmed and well-documented occurrence of edoylerite in the world is its type locality – the Socrates Mine in Sonoma County, California, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of edoylerite specimens is primarily judged by the size and development of the crystals. Specimens with sharp, well-formed crystals of intense yellow color and strong luster are most valued. The aesthetics of the composition are also important – attractively arranged crystals on a contrasting rock matrix. Due to the microscopic nature of the mineral, even small aggregates of well-formed crystals are considered valuable. ## Popular Localities The only source of collectible specimens is the Socrates mine in California. Material from this locality is extremely rare and sought after by collectors specializing in systematic minerals, rare species, or "micromount" minerals.

Care and storage

## Cleaning Edoylerite specimens should be handled with the utmost care. Due to its toxicity and fragility, mechanical cleaning is strongly discouraged. If absolutely necessary, compressed air (from a safe distance) can be used to remove loose dust particles. Avoid contact with water and all chemicals. ## What to Avoid The mineral is sensitive to light and may darken with prolonged exposure. Avoid vibrations, shocks, and temperature changes. Contact with acids or other chemical reagents can destroy it. Due to its mercury content, it is absolutely essential to avoid inhaling dust and direct skin contact. Wash hands thoroughly after each contact with the specimen. ## Storage Edoylerite must be stored in a sealed, stable container, preferably a "micromount" type, away from sunlight and heat sources. The container should be clearly labeled as toxic. Store in a dry place, away from other minerals that could react with it.