Beryllonite
Current inventory:  2 gems
 

  
Beryllonite is named for its chemical composition containing BERYLLium.

Discovered in 1888;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

NaBe(PO₄)

Sodium Beryllium Phosphate

Molecular Weight:

126.97 gm

Composition:

Sodium

18.11 %

Na

24.41 %

Na₂O

Beryllium

7.10 %

Be

19.70 %

BeO

Phosphorus

24.39 %

P

55.90 %

P₂O₅

Oxygen

50.40 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/A.01-30

Nickel-Strunz 10th Ed. ID:

8.AA.10

8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H₂O
A : With small cations (some also with larger ones)

Related to:

n/a

Varieties:

None

Synonyms:

None

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Tabular on {010} to short prismatic || [010]; crystals may have many forms, especially k [100] and [010]; some faces typically etched to dullness, to 25 cm; also in spherical aggregates, fibrous, massive.

Twinning:

On {101}, contact and penetration twins; on {110} and {100} polysynthetic and pseudohexagonal stellate twins.

Physical Properties

Cleavage:

Perfect on {010}, Good but Interrupted on {100}, Indistinct on {101}, in traces on {001}

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

5.5 - 6.0

Density:

7.12 - 7.20 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Fluid inclusions common. Slowly soluble in acids. Alters to Herderite.

Optical Properties

Color:

Colorless, White, Pale yellow

Transparency:

Transparent to Translucent

Luster:

Vitreous to Adamantine, may be Pearly

Refractive Index:

1.552 - 1.561  Biaxial ( - )

Birefringence:

0.0090

Dispersion:

Weak to Distinct; r < v

Pleochroism:

None

Other:

Fluid inclusions common.

Occurances

Geological Setting:

A rare secondary mineral in granitic and alkalic pegmatites.

Common Associations:

Herderite, Triplite, Beryl, Apatite, Cassiterite, Columbite, Eosphorite, Morinite, Väyrynenite, Lithiophilite, Elbaite, Pollucite, Petalite, Lepidolite, Albite, Orthoclase, Quartz.

Common Impurities:

None

Co-Type Localities:

Joe McKeen Mountain locality (McKean Mountain), Lovell, Oxford County, Maine, USA;
Melrose Farm Beryllonite prospects (McAllister prospects), Stoneham, Oxford County, Maine, USA

Year Discovered:

1888

View mineral photos:

Beryllonite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Beryllonite is a rare beryllium mineral and a very rare collector's gem that was once found only at mines on Sugarloaf Mountain, near Stoneham, Maine, USA. It is now also available from Paprock, Laghman Province, Afghanistan and Linopolis, Minas Gerais, Brazil. It is a difficult gem to cut because of its perfect basal cleavage. Beryllonite gems lack color, fire and hardness but are very collectible due to their rarity. Beryllonite crystals form in pegmatitic dikes and can easily be confused with more common pegmatite minerals.

Locations for Beryllonite include: in the USA, in Maine, found on Sugarloaf Mountain, near Stoneham, at the Dunton quarry and the Bell Pit, Newry, Oxford County, and other minor occurrences. In Canada, occurs at Mont Saint-Hilaire, Quebec. Found at the Viitaniemi pegmatite, Eräjärvi, Finland. From the Norrö pegmatite, on Rånö Island, Sweden. In England, in the Meldon aplite, Okehampton, Devonshire. Large crystals from Paprock, Laghman Province, Afghanistan. Occurs in the Énio pegmatite mine, northeast of Galiléia; at the Lavra da Ilha pegmatite, in the Jequitinhonha River, three km north of Taquaral; and from the Almerindo mine, Linópolis, Minas Gerais, Brazil.
 

  
Beryllonite gems for sale: