Loranskite-(Y)
Chemical formula: (Y,Ce³⁺,Ca)(Zr⁴⁺,Ta⁵⁺)₂O₆
Loranskite-(Y) is a rare, black oxide mineral containing yttrium and zirconium, found in granitic pegmatites.
Properties
- Mohs hardness
- 5
- Color
- Black; greenish yellow (transmitted light)
- Luster
- Resinous
- Streak
- Green-grey
- Density
- 4.6
- Cleavage
- None
- Fracture
- Conchoidal
- Transparency
- Opaque
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Loranskite-(Y) can be identified by its black color, resinous luster, high density, and occurrence in granitic pegmatites. A key diagnostic feature is its radioactivity, which can be detected with a Geiger counter. Under laboratory conditions, the ultimate confirmation is chemical composition analysis, which shows the presence of yttrium, zirconium, and tantalum. ## Distinguishing from Similar Minerals It can be confused with other black, heavy pegmatitic minerals such as euxenite-(Y), samarskite-(Y), columbite, or tantalite. Distinguishing it from euxenite-(Y) and samarskite-(Y) is visually practically impossible and requires advanced studies (e.g., X-ray diffraction). It generally differs from columbite and tantalite by having less well-formed crystals and a lack of distinct cleavage. ## Crystal Forms Loranskite-(Y) crystals are very rare and poorly formed, with a prismatic habit. Most often, it occurs as irregular, embedded aggregates and grains.
Geological environment
## Genesis Loranskite-(Y) is an accessory mineral, formed in the late stages of crystallization of granitic pegmatites, especially those enriched in rare earth elements (REE), zirconium, niobium, and tantalum. ## Mineral Associations It most commonly co-occurs with minerals typical of the pegmatitic environment, such as albite, microcline, quartz, biotite, zircon, xenotime-(Y), monazite-(Ce), fergusonite-(Y), and other minerals from the euxenite group. ## Localities The most important and classic localities for this mineral are: - Russia: Impilahti in Karelia (type locality). - Norway: pegmatites in the Setesdalen region (e.g., Iveland) and in the Kragerø area. - Sweden: Ytterby near Stockholm. - United States: rarely in pegmatites in Texas (Barringer Hill) and Colorado.
Rarity
Very rare
For collectors
## Quality Criteria The collector's appeal of loranskite-(Y) primarily depends on its rarity and locality. Specimens with well-formed, even if partially, crystals are most valued, which is a great rarity for this mineral. The size of the specimen and its association with other minerals (paragenesis), forming an aesthetic composition on the rock matrix, are also important. Purity and intensity of luster also increase value, although it is often dull due to weathering. ## Popular Localities Specimens from classic, historical localities, such as Impilahti in Russia or pegmatites in Norway (Iveland, Kragerø), are particularly sought after by collectors specializing in mineral systematics or rare earth minerals.
Care and storage
## Cleaning Loranskite-(Y) specimens should only be cleaned mechanically, using a soft, dry brush or paintbrush to remove dust. Due to its brittleness and possible presence of weathering products, avoid washing with water and any chemical agents. ## What to Avoid The mineral is sensitive to chemicals, so contact with acids and other solvents should be avoided. As a metamict mineral, it is relatively stable, but it should not be heated. Due to its radioactivity, direct, prolonged contact should be limited, and it should be stored away from other radiation-sensitive minerals. ## Storage It is recommended to store specimens in separate, padded boxes to prevent abrasions and mechanical damage. They should be kept in a dry place, away from specimens that may be damaged by radiation (e.g., some varieties of quartz, fluorite). Always wash hands after contact with the mineral.