Beryllonite

minerals

triplite

herderite

morinite

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Formula: NaBe(PO4)
Anhydrous normal phosphate, alters to herderite (Mindat).
Specific gravity: 2.77 to 2.85
Hardness: 5½ to 6
Streak: White
Colour: Colourless, white, rarely pale light yellow; colourless in transmitted light.
Solubility: Slowly soluble in acids
Environments:

Pegmatites

Beryllonite is a rare secondary mineral in granitic and alkaline pegmatites, associated with herderite, triplite, beryl, apatite, cassiterite, columbite, eosphorite, morinite, väyrynenite, lithiophilite, elbaite, pollucite, petalite, lepidolite, albite, orthoclase and quartz (HOM, Webmin).

Localities

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, beryllonite has been found, but usually it has been replaced by such species as hydroxylherderite. The Emmons pegmatite is an example of a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.505).

At the Dunton quarry, Newry, Oxford county, Maine, USA, beryllonite occurs with hydroxylherderite and elbaite (Dana).

At the type localities, Stoneham, Oxford county, Maine, USA, beryllonite occurs in a granite pegmatite associated with triplite, smoky quartz, muscovite, microcline, fluorapatite, cassiterite, beryl and albite. (Mindat, Dana). It is the oldest of the phosphates to form here, often coated with herderite, which is a product of its alteration (AM13.392).

At the Chickering Mine, Cheshire county, New Hampshire, USA, beryllonite crystals are found in small cavities of milky quartz and montebrasite, associated with apatite and muscovite (R&M 90-5.414).

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