Silinaite

Chemical formula: NaLiSi₂O₅·2H₂O

Silinaite is a rare sodium lithium silicate, forming colorless, fibrous aggregates, found in xenoliths within alkaline intrusions.

## Characteristics Silinaite is a hydrated sodium lithium silicate that visually presents as colorless to white, silky aggregates. It typically forms massive, felted masses of fine, flexible fibers, which can reach up to 1 cm in length. This mineral is very rare and occurs in a specific geological environment. ## Physical Properties Silinaite is characterized by a silky luster on the surfaces of its aggregates. It is a soft mineral, with a Mohs hardness of approximately 2.5. Its fibers are flexible. It is translucent to opaque. The calculated density is 2.36 g/cm³. ## Colors and Varieties This mineral is typically colorless to white. No colored or commercial varieties have been identified. ## History and Name Silinaite was first described in 1991 by G.Y. Chao, J.D. Grice, and R.A. Gault. Its name is derived from its chemical composition, emphasizing the presence of silicon (Latin: *silex*), sodium (Latin: *natrium*), and lithium. ## Uses Due to its extreme rarity, silinaite has no industrial applications and is solely an object of scientific and collecting interest.

Properties

Mohs hardness
4.5
Color
Colourless, white
Luster
Silky
Streak
White
Density
2.24
Cleavage
{001} perfect, {010} good, and {110} distinct
Fracture
Conchoidal
Transparency
Transparent,Translucent,Opaque
Crystal system
Monoclinic

Diagnostic features

## Identification Silinaite can be identified by its characteristic, silky, fibrous aggregates of white or colorless appearance. A key feature is its reaction to water – it is soluble in it. Its fibrous structure and low hardness are also important indicators. ## Distinguishing from Similar Minerals It can be confused with other fibrous minerals, such as asbestiform serpentine, tremolite, or some zeolites (e.g., natrolite). It is distinguished from them primarily by its solubility in water and exceptional delicacy. Unlike many zeolites, it does not form radial aggregates, and its fibers are felted. ## Crystal Forms Silinaite occurs as aggregates of very fine, flexible fibers that form felted or fibrous masses. Individual crystals are too small to be observed with the naked eye.

Geological environment

## Genesis Silinaite forms under very specific conditions. It occurs in xenoliths of sodalite syenites that have been entrained and displaced within a nepheline syenite intrusion. It is a product of hydrothermal processes occurring in the late stage of alkaline magma crystallization. ## Mineral Associations This mineral coexists with other rare alkaline minerals, such as sodalite, stephanite, analcime, aegirine, microcline, pectolite, and also with newly discovered minerals like monteregianite-(Y). ## Localities The only confirmed occurrence of silinaite in the world is the Poudrette quarry at Mont Saint-Hilaire in Quebec, Canada. This is its type locality.

Rarity

Extremely rare

For collectors

## Quality Criteria The most prized silinaite specimens are those that exhibit rich, pure white, silky fibrous aggregates on a contrasting rock matrix. The abundance of material and the absence of damage to the delicate fibers are important. Due to its rarity, any well-formed specimen is valuable. ## Popular Localities The only source of silinaite specimens is the Poudrette quarry at Mont Saint-Hilaire, Canada. Specimens from this locality are highly sought after by collectors specializing in rare minerals and those from this specific locality.

Care and storage

## Cleaning Silinaite specimens are extremely delicate and sensitive to water. Mechanical cleaning is not recommended. If necessary, compressed air can be used from a distance to remove loose dust particles. ## What to Avoid Contact with water, which can dissolve or damage the mineral, must be strictly avoided. All chemicals, ultrasound, and high temperatures should also be avoided. The specimen is very soft and susceptible to mechanical damage. ## Storage It is recommended to store specimens in tightly sealed, dry containers (e.g., "perky box" type), away from moisture, heat sources, and direct sunlight. It should be protected from dust and shocks.

External references

Sources

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