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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:
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At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, beryllonite has been found, but usually it has been replaced
by such species as hydroxylherderite.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).
There are two co-type localities, the Beryllonite Locality (Mcallister Occurrence), and the Joe McKeen Mountain
locality, both at Stoneham, Oxford County, Maine, USA. At the type localities 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).
In New Hampshire, USA, beryllonite has been reported from only a few mines, with the best specimens occurring at
the Palermo No. 1 mine in Groton, Chandlers Mill mine in Newport, and Chickering mine in Walpole. Crystals are
colourless or white to pale yellow and rarely exceed 1.5 mm
(R&M 97.3.218).
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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