Barylite

barylite

hedyphane

bastnasite

eudialyte

Formula: BaBe₂Si₂O₇
Sorosilicate (Si₂O₇ groups) of barium and beryllium
Crystal System: Orthorhombic
Specific gravity: 4.066 measured, 4.01 calculated
Hardness: 7
Streak: White
Colour: Bluish white, colourless
Luminescence: May fluoresce vivid blue under UV
Common impurities: Al,Fe,Zn,Pb,Mg,Ca
Environments:

Plutonic igneous environments
Pegmatites
Metamorphic environments

Barylite occurs in alkalic pegmatites and miarolitic cavities, and also in nephelene syenite and other alkalic intrusions (Webmin)

Localities

At the Seal Lake alkaline complex, Labrador, Newfoundland and Labrador, Canada, barylite occurs in narrow veins in chert-like silica and albite in fenitised gneiss associated with eudialyte (HOM).
Beryllium mineralisation occurs in two ways:
(1) as high-grade barylite-bearing veinlets cutting fenitised gneiss
(2) as disseminated grains of barylite in fenitised gneiss
The material is slightly radioactive. The veins also contain aegirine - augite, microcline, albite and accessory bastnäsite, aeschynite, baryte, strontianite, thorite variety thorogummite, harmotome, fluorite, quartz, sulphides, and TiO₂ minerals. The Seal Lake barylite has been formed as a product of alkali metasomatism in fenitised amphibole gneiss. The accumulation of beryllium in barylite, marginal to the intrusive, accompanies a paucity of beryllium in the intrusive itself (AM 47.758-763).

At the Narssârssuk pegmatite, Narsaarsuk Plateau, Igaliku, Kujalleq, Greenland, barylite occurs in a nephelene syenite pegmatite (HOM).

At the Vishnevye-Ilmen Mountains, Chelyabinsk Oblast, Russia, barylite occurs in calcite veins cutting amphibole gneiss associated with bastnäsite, aeschynite, baryte, strontianite, thorite variety thorogummite, harmotome, fluorite and quartz (HOM).

At the type locality, the Långban mine, Långban Ore District, Filipstad, Värmland County, Sweden, barylite is associated with hedyphane (HOM).

At Park county, Colorado, USA, barylite is associated with microcline, baryte and fluorite (HOM).

At the Franklin Mine, Franklin, Franklin Mining District, Sussex County, New Jersey, USA, barylite occurs in a well-banded vein, in a metamorphosed stratiform zinc orebody, embedded with hedyphane and some willemite. Other vein associates were calcite, native copper, and serpentine, the last cementing the brecciated barylite. (AM 47.758, HOM).

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