Beryllonite
Beryllonite is NaBePO4, a colourless sodium beryllium phosphate of pegmatites: hardness 5.5–6, density 2.77–2.84, 7.10% beryllium. How it ties with quartz.
Beryllonite is NaBe(PO4) on the September 2026 IMA list: a monoclinic, pseudo-orthorhombic sodium beryllium phosphate of granitic and alkalic pegmatites, colourless to pale yellow, hardness 5.5–6, density 2.77–2.84. Worked, it is 7.10% beryllium. Its birefringence, 0.009, is exactly quartz’s, so a refractometer alone will not separate the two.
In short
- The species. The Handbook of Mineralogy sheet gives monoclinic, pseudo-orthorhombic crystals, tabular on {010} to short prismatic, to 25 cm, some faces etched to dullness; perfect {010} cleavage; hardness 5.5–6; density 2.77–2.84; colourless, white to pale yellow; vitreous to adamantine, pearly on {010}; biaxial (−). The September 2026 IMA-CNMNC Master List row reads NaBe(PO4), status G, 1888, USA.
- The 0.009 tie. The sheet’s indices are α 1.552, β 1.558, γ 1.561: birefringence 0.009. Quartz’s sheet gives ω 1.544 and ε 1.553: also 0.009. The two index windows touch at 1.552–1.553. What separates them is the optic class (biaxial − against uniaxial +), the hardness (5.5–6 against 7), the perfect, pearly {010} cleavage, and the weight: 12.78–12.96 g in water for 20.00 g against quartz’s 12.45 g.
- The 7.10% twin. On standard atomic weights sodium plus phosphorus, 22.990 + 30.974, is 53.964, and two aluminium, 2 × 26.982, is also 53.964. So NaBePO4 and chrysoberyl, BeAl2O4, both weigh 126.97 g/mol and are both 7.10% beryllium. phenakite is 16.37%, beryl 5.03%.
- Is it a gem? Muyal and Sun, Gems & Gemology, Fall 2016 call beryllonite a gem, typically fashioned as a transparent colourless faceted stone and occasionally as a cat’s-eye cabochon; they linked its chatoyancy to parallel growth tubes left where minute inclusions blocked growth. The sheet itself does not use the word.
- Where it is found. The sheet’s Distribution names Maine (Stoneham; the Dunton quarry and Bell Pit, Newry), Mont Saint-Hilaire in Quebec, Finland, Sweden, the Meldon aplite near Okehampton in Devon, large crystals from Paprock, Laghman Province, Afghanistan, and three pegmatites in Minas Gerais, Brazil. It does not name Pakistan.
| Species | IMA formula | System (sheet) | Hardness | Density (sheet) | Indices (sheet) | Birefringence, worked | Optic class | Be by mass | 20.00 g in water |
|---|---|---|---|---|---|---|---|---|---|
| Beryllonite | NaBe(PO4) | Monoclinic, pseudo-orthorhombic | 5.5–6 | 2.77–2.84 | 1.552, 1.558, 1.561 | 0.009 | Biaxial (−) | 7.10% | 12.78–12.96 g |
| Quartz | SiO2 | Hexagonal | 7 | 2.65 | ω 1.544, ε 1.553 | 0.009 | Uniaxial (+) | None | 12.45 g |
| Herderite | CaBe(PO4)F | Monoclinic | 5–5.5 | 3.02 | α 1.556–1.59, γ 1.589–1.62 | 0.030–0.033 | Biaxial (−) | 5.53% | 13.38 g |
| Hydroxylherderite | CaBe(PO4)(OH) | Monoclinic | 5–5.5 | 2.95 | α 1.59–1.615, γ 1.62–1.643 | 0.028–0.030 | Biaxial (−) | 5.60% | 13.22 g |
| Phenakite | Be2(SiO4) | Hexagonal | 7.5–8 | 2.93–3.00 | ω 1.650–1.656, ε 1.667–1.670 | 0.014–0.017 | Uniaxial (+) | 16.37% | 13.17–13.33 g |
| Beryl | Be3Al2(Si6O18) | Hexagonal | 7.5–8 | 2.63–2.97 | ω 1.567–1.610, ε 1.565–1.599 | 0.002–0.011 | Uniaxial (−) | 5.03% | 12.40–13.27 g |
What is beryllonite? A sodium beryllium phosphate of pegmatites
Beryllonite is NaBePO4, a monoclinic, pseudo-orthorhombic phosphate that its sheet calls a rare secondary mineral in granitic and alkalic pegmatites. The Handbook of Mineralogy beryllonite sheet describes crystals tabular on {010} to short prismatic, with many forms, some faces typically etched to dullness, to 25 cm, and also spherical aggregates, fibrous and massive habits. It records contact and penetration twins on {101} and polysynthetic and pseudohexagonal stellate twins on {110} and {100}. Hardness is 5.5–6, density 2.77–2.84 measured and 2.805 calculated; the cleavage is perfect on {010}, good but interrupted on {100}, and the fracture conchoidal.
What the lists record. The September 2026 IMA-CNMNC Master List writes NaBe(PO4), status G (grandfathered), year 1888, country USA. It is the only IMA row built from sodium, beryllium and phosphate alone, by a script over the list’s formula column. The name is for one of its major constituents, BERYLLium (sheet). Type material is at Yale University; the sheet marks no type locality, so this page names none (what a type locality is).
The cell, worked. The printed cell, 8.178 × 7.818 × 14.114 Å with β = 90.00°, holds 902.39 ų. Twelve formula units of 126.97 g/mol give 12 × 126.97 ÷ (0.60221 × 902.39) = 2.804 g/cm³, against the printed 2.805, and the composition column reproduces: P2O5 55.90%, BeO 19.70%, Na2O 24.41% worked, 55.89, 19.70 and 24.41 printed. The Stoneham analysis, a composite of six partial analyses, totals 99.42.
Can beryllonite be mistaken for quartz? The 0.009 tie
Yes, on a refractometer: beryllonite’s birefringence is 0.009 and so is quartz’s, and their index windows meet. The beryllonite sheet prints α 1.552, β 1.558, γ 1.561; the quartz sheet prints ω 1.544 and ε 1.553. Both differences are 0.009, and beryllonite’s lowest index sits 0.001 below quartz’s highest. A colourless piece reading about 1.55 with a birefringence of 0.009 is therefore not identified by those two numbers.
What breaks the tie. Beryllonite is biaxial (−) with a 2V near 68°; quartz is uniaxial (+). Beryllonite is 5.5–6 in hardness, quartz 7 (how to test mineral hardness properly). Beryllonite has a perfect {010} cleavage that may show a pearly lustre; quartz’s sheet calls its cleavage rarely observable. And on the balance a 20.00 g piece reads 12.78–12.96 g in water as beryllonite against 12.45 g as quartz, a gap of at least 0.33 g (how to measure specific gravity at home).
Documented failure: herderite. herderite, on beryllonite’s own association line, is also colourless-to-pale, biaxial (−) and soft, and its α range, 1.556–1.59, overlaps beryllonite’s 1.552–1.561. Its birefringence, 0.030–0.033 worked, is more than three times beryllonite’s, and 20.00 g reads 13.38 g in water, so the balance and the index spread separate them where the sign does not. phenakite’s separation from quartz is its own page’s subject and is not repeated here.
How much beryllium is in beryllonite? The 7.10% twin
7.10% by mass, the same as chrysoberyl, because the two formulas weigh the same. On standard atomic weights NaBePO4 is 22.990 + 9.0122 + 30.974 + 4 × 15.999 = 126.97 g/mol, of which beryllium is 9.0122, or 7.10%. In BeAl2O4 the sodium and phosphorus are replaced by two aluminium atoms; 22.990 + 30.974 = 53.964 and 2 × 26.982 = 53.964, so chrysoberyl is also 126.97 g/mol and 7.10% beryllium. The coincidence is arithmetic, not chemistry: the two are a phosphate and an oxide.
Against its neighbours. Worked from the IMA formulas, phenakite is 16.37% beryllium, bertrandite 15.13%, hurlbutite CaBe2(PO4)2, named in the sheet’s references, 7.27%, euclase 6.21%, hydroxylherderite 5.60%, herderite 5.53% and beryl 5.03%. Beryllonite sits with chrysoberyl in the middle of that list.
Beryllium-bearing dust is a hazard question this page does not answer; it is routed to toxic minerals in a collection, and nothing here is advice.
Where is beryllonite found? Maine, Devon, Afghanistan and Brazil
The beryllonite sheet’s Distribution, as printed. In the USA, in Maine, on Sugarloaf Mountain, near Stoneham, at the Dunton quarry and the Bell Pit, Newry, Oxford Co., and other minor occurrences. In Canada, at Mont Saint-Hilaire, Quebec. The Viitaniemi pegmatite, Eräjärvi, Finland. The Norrö pegmatite, on Rånö Island, Sweden. In England, in the Meldon aplite, Okehampton, Devonshire (Devon). Large crystals from Paprock, Laghman Province, Afghanistan. In Minas Gerais, Brazil, the Énio pegmatite mine northeast of Galiléia, the Lavra da Ilha pegmatite in the Jequitinhonha River three km north of Taquaral, and the Almerindo mine, Linópolis. The X-ray pattern is from Stoneham. We add no other locality.
Beryllonite and Pakistan. People search for beryllonite from Pakistan. The sheet’s Distribution does not name Pakistan, and this page does not add a country from a dealer or gem-trade source; Afghanistan’s Paprock is the nearest place the sheet prints. The associates the sheet names are herderite, triplite, beryl, apatite, cassiterite, columbite, eosphorite, morinite, väyrynenite, lithiophilite, elbaite, pollucite, petalite, lepidolite, albite, orthoclase and quartz.
Related pegmatite species, spodumene and topaz among them, are in the species index. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.