Gerenite-(Y)

Chemical formula: NaCaY₃Si₆O₁₈·₂H₂O

Gerenite-(Y) is a very rare yttrium, calcium, and sodium silicate, forming small, prismatic crystals with a vitreous luster.

## Characteristics Gerenite-(Y) is a complex rare-earth element silicate, primarily yttrium, as well as calcium and sodium. It belongs to the ekanite group of minerals. It occurs as very small, elongated, prismatic crystals, reaching sizes up to 0.2 mm. The crystals are colorless to pale pink and exhibit a vitreous luster. Due to its extreme rarity and small crystal size, it is a mineral of purely scientific and collector interest. ## Physical Properties This mineral is characterized by a hardness of approximately 5 on the Mohs scale. Its crystals are transparent. The density calculated from the formula and unit cell parameters is 3.45 g/cm³. No fluorescence has been observed in it. ## Colors and Varieties Gerenite-(Y) is typically colorless, less commonly adopting pale pink hues. No varieties have been distinguished. ## History and Name The mineral was discovered in the Poudrette quarry at Mont Saint-Hilaire, Quebec (Canada). It was described in 1996 by George Y. Chao, Joel D. Grice, and Robert A. Gault. The name "gerenite" honors Richard Geren (1917–2002), president of the Iron Ore Company of Canada, in recognition of his contribution to the development of the Canadian mining industry. The "-(Y)" suffix in the name indicates yttrium as the dominant rare-earth element in its composition.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: White
Density: 3.45
Cleavage: None
Fracture: Uneven
Transparency: Transparent
Crystal system: Tetragonal

Diagnostic features

## Identification Identifying gerenite-(Y) is extremely difficult without advanced analytical methods. Recognition relies on chemical analysis (EDS/WDS) to confirm the presence of sodium, calcium, yttrium, and silicon, and on X-ray diffraction (XRD) to determine the crystal structure. Visually, it is practically indistinguishable from many other colorless microscopic minerals. ## Distinguishing from Similar Minerals It can be confused with many other minerals from the ekanite group or other colorless silicates found at Mont Saint-Hilaire, such as quartz, albite, or analcime. Definitive differentiation requires specialized laboratory tests. ## Crystal Forms Gerenite-(Y) forms elongated, prismatic crystals with a square cross-section. The crystals are terminated by a tetragonal pyramid. They occur as single, isolated crystals on the surface of other minerals.

Geological environment

## Genesis Gerenite-(Y) forms in the late stages of crystallization in pegmatites and sodalite xenoliths within alkaline nepheline syenite intrusions. It is a hydrothermal mineral, crystallizing in fractures and rock vugs. ## Mineral Associations At the type locality (Mont Saint-Hilaire), gerenite-(Y) coexists with minerals such as albite, microcline, aegirine, nepheline, sodalite, eudialyte, catapleiite, steacyite, and vinogradovite. ## Localities The only confirmed occurrence of gerenite-(Y) in the world is the Poudrette quarry, located on Mont Saint-Hilaire in the Montérégie region, Quebec province, Canada. This is its type locality.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a gerenite-(Y) specimen is primarily determined by its confirmed analytical identity. Due to their microscopic size, specimens with well-formed, sharp crystals visible under magnification are most valued. The aesthetics of the rock matrix and the presence of rare associated minerals are also important. ## Popular Localities All known specimens come from a single location in the world – the Poudrette quarry at Mont Saint-Hilaire in Canada. This locality is known for hundreds of unique and rare minerals, and specimens from there are highly prized by collectors specializing in systematic minerals and "micromounts."

Care and storage

## Cleaning Due to the extreme rarity and small size of its crystals, gerenite-(Y) specimens usually occur on a rock matrix and should not be cleaned mechanically. If necessary, compressed air can be used to remove dust. Contact with water and chemical agents should be avoided. ## What to Avoid Avoid ultrasonics, steam cleaners, acids, and any chemical solvents. The mineral should be protected from sudden temperature changes and direct, prolonged exposure to sunlight. ## Storage Specimens should be stored under stable conditions, preferably in a sealed "micromount" box, to protect them from dust, mechanical damage, and humidity. Storage in a dark and dry place will help preserve their original condition.

Sources

IMA Mineral List (CNMNC)