Emilite

Chemical formula: Cu₁+₁₀.₇Pb₂+₁₀.₇Bi₃+₂₁.₃S₂-₄₈

Emilite is an extremely rare sulfosalt of copper, lead, and bismuth, known exclusively from a single deposit in Sweden.

## Characteristics Emilite is a complex sulfosalt belonging to the lillianite group. It forms anhedral, platy grains not exceeding 0.5 mm in size. It typically occurs as complicated intergrowths with other similar minerals, making its macroscopic identification impossible. It has a steel-gray to black color and a metallic luster. ## Physical Properties The Mohs hardness of emilite is 3.5. It is a brittle and opaque mineral. Its density, calculated based on chemical composition and unit cell parameters, is 7.13 g/cm³. No cleavage has been observed. ## Colors and Varieties This mineral is uniform in color – it occurs in shades from steel-gray to black. No colored or commercial varieties are known. ## History and Name Emilite was recognized as a new mineral species by the International Mineralogical Association (IMA) in 1999. Its name honors Emil Makovicky (born 1940), Professor of Mineralogy at the University of Copenhagen, in recognition of his fundamental contributions to the crystal chemistry of sulfosalts. ## Applications Due to its extreme rarity and microscopic size, emilite has no commercial or industrial applications. It is solely an object of scientific research and interest for specialized collectors of systematic minerals.

Properties

Mohs hardness: 3.5
Luster: Metallic
Streak: Black
Density: 7.13
Transparency: Opaque
Crystal system: Orthorhombic

Diagnostic features

## Identification Identification of emilite is impossible without advanced analytical techniques. Due to its occurrence as microscopic, intergrown grains with an appearance similar to many other sulfosalts, the only reliable method of identification is chemical microanalysis (EDS/WDS) combined with crystallographic studies. ## Distinguishing from Similar Minerals Emilite is visually indistinguishable from coexisting minerals such as cosalite, lillianite, heyrovskýite, or bismuthinite. All these minerals have a similar metallic luster, gray color, and occur in similar forms. Definitive differentiation requires specialized laboratory equipment. ## Crystal Forms Emilite does not form well-developed crystals. It occurs exclusively as anhedral, platy grains and aggregates, forming complex intergrowths with other minerals within the host rock.

Geological environment

## Genesis This mineral forms under hydrothermal conditions, in quartz-siderite veins. ## Mineral Associations Emilite occurs in close association with other lead and bismuth sulfosalts, such as bismuthinite, cosalite, lillianite, heyrovskýite, as well as with quartz and siderite. ## Localities The only confirmed locality of emilite in the world is the historic Vena mine in the Hammar area (Askersund municipality) in Sweden. This is its type locality.

Rarity

Extremely rare

For collectors

## Quality Criteria The collector's value of emilite is almost exclusively scientific and systematic. Since specimens are microscopic grains in rock, their value is primarily determined by the certainty of identification confirmed by chemical analysis. The visual attractiveness of a specimen depends on the possible presence of better-formed associated minerals. ## Popular Localities The only source of specimens is the type locality – the Vena mine in Sweden. Material from this location is extremely difficult to obtain.

Care and storage

## Cleaning Emilite specimens, being microscopic inclusions in rock, should not be wet cleaned. At most, a soft brush or a stream of compressed air can be used to remove dust. Any mechanical intervention risks damaging the delicate grains. ## What to Avoid Avoid contact with water, chemical agents (especially acids), and ultrasonic cleaners. As a sulfosalt, this mineral can be susceptible to oxidation in a humid environment, leading to its slow decomposition. ## Storage It is recommended to store specimens in a dry place, preferably in a tightly sealed "micromount" box, which protects against dust, moisture, and sudden temperature changes.

Sources

IMA Mineral List (CNMNC)