Åskagenite-(Nd)

Chemical formula: Mn₂+Nd(Al₂Fe₃+)[Si₂O₇][SiO₄]O₂

Åskagenite-(Nd) is a very rare mineral from the epidote group, characterized by the presence of neodymium and a complex silicate structure.

## Characteristics Åskagenite-(Nd) is an extremely rare mineral belonging to the epidote group. It forms black, submetallic, prismatic crystals that usually do not exceed 1 mm in length. They occur as radial aggregates or single needles embedded in the rock. The mineral is opaque and brittle. ## Physical Properties It is characterized by a Mohs hardness of 6-7 and a density of approximately 4.83 g/cm³. The luster is submetallic, and the streak is gray. It shows no cleavage, and its fracture is uneven. ## History and Name The mineral's name comes from its discovery locality – the Åskagen pegmatite quarry, located near Filipstad in the Värmland region of Sweden. It was officially recognized by the International Mineralogical Association (IMA) in 2011. The "-(Nd)" suffix in the name indicates the dominant rare-earth element in its composition – neodymium.

Properties

Mohs hardness: 6-7
Luster: Submetallic
Streak: Gray
Density: 4.83
Cleavage: None
Fracture: Uneven
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of Åskagenite-(Nd) is almost exclusively possible using advanced laboratory methods, such as electron spectroscopy (EDS/WDS) for chemical composition analysis and X-ray diffraction (XRD) to determine crystal structure. Visually, it is a black, submetallic mineral forming small, prismatic crystals. ## Distinguishing from Similar Minerals It can be confused with other black minerals from the epidote group, such as allanite or ferriallanite, as well as with tourmaline (schorl) or ilmenite. Certain differentiation requires specialized chemical analysis, which will show the dominance of neodymium over other rare-earth elements. ## Crystal Forms It forms elongated, prismatic crystals with a rhombic cross-section, often terminated by steep faces. These crystals occur as single needles or form radial, star-shaped aggregates embedded in the rock matrix.

Geological environment

## Genesis Åskagenite-(Nd) forms in rare-earth-rich granitic pegmatites. It is a late-stage crystallization mineral, forming in altered (metasomatized) parts of the pegmatite. ## Mineral Associations This mineral coexists with quartz, microcline, almandine, fergusonite-(Y), xenotime-(Y), allanite-(Ce), titanite, zircon, magnetite, and fluorite. ## Localities The only confirmed occurrence (type locality) is the Åskagen quarry in Värmland, Sweden. This is the only known locality for this mineral in the world.

Rarity

Extremely rare

For collectors

## Quality Criteria Due to its extreme rarity, every analytically confirmed specimen of Åskagenite-(Nd) is extremely valuable. The most highly prized specimens are those with well-formed, sharp crystals forming aesthetic, radial aggregates on a contrasting matrix (e.g., on white quartz or feldspar). The size of the crystals, even if exceeding 1 mm, significantly increases the value of the specimen.

Care and storage

## Cleaning Due to its extreme rarity and small crystal size, mechanical cleaning is not recommended. If absolutely necessary, compressed air can be used to remove loose dust. Avoid contact with water and chemicals. ## What to Avoid Avoid all chemicals, acids, and ultrasonics, which can irreversibly damage delicate crystals. The mineral should be protected from moisture and sudden temperature changes. ## Storage Åskagenite-(Nd) specimens are typically microscopic and stored in specialized micromount boxes. They should be kept in a stable, dry environment, away from direct sunlight and dust.

Sources

IMA Mineral List (CNMNC)