Beryllonite Mineral Overview

Mineral name: Beryllonite
Mineral class: Phosphate

Known Facts

• Chemical formula: NaBePO₄
• Crystal system: Monoclinic
• Mohs hardness: 5.5–6
• Color range: Colorless, white, pale yellow
• Luster: Vitreous
• Streak: White
• Cleavage: Perfect in one direction
• Fracture: Uneven to subconchoidal
• Specific gravity: Approximately 2.8–2.9
• Common locations: United States (New Hampshire), Brazil
• Uses: Collector specimens, rare gemstone
• Similar minerals: Phenakite, quartz, other beryllium minerals

Physical and Optical Characteristics

Beryllonite typically occurs as:

• Tabular or prismatic crystals
• Massive or granular aggregates

Crystals are often transparent to translucent, and gem-quality material can be quite clear.

Color is usually colorless or white, sometimes with a faint yellow tint. Due to its lack of strong coloration, it may be overlooked in the field.

The luster is vitreous, giving it a glassy appearance. A defining feature is its perfect cleavage, which makes it:

• Brittle
• Difficult to cut as a gemstone despite moderate hardness

Chemical Composition and Structure

Beryllonite has the formula:

• NaBePO₄

It is a sodium beryllium phosphate, containing:

• Sodium (Na)
• Beryllium (Be)
• Phosphate groups (PO₄³⁻)

It is one of the few minerals combining beryllium and phosphate in a relatively simple composition.

Its structure contributes to:

• Good crystal clarity
• Pronounced cleavage

Formation and Geological Occurrence

Beryllonite forms in granitic pegmatites, particularly in beryllium-rich environments.

Typical formation conditions include:

• Late-stage crystallization in pegmatitic systems
• Enrichment in beryllium and phosphorus

It is commonly associated with:

• Beryl
• Quartz
• Feldspar
• Other phosphate minerals

It may occur in cavities or intergrown with other pegmatite minerals.

Common Locations

Notable occurrences of Beryllonite include:

• United States: New Hampshire (type locality, Stoneham)
• Brazil: Pegmatite deposits

New Hampshire is historically important for early discoveries of the mineral.

Uses and Practical Significance

Beryllonite has limited practical use:

Gemstone

• Occasionally cut into faceted stones
• Limited by:
  • Perfect cleavage
  • Fragility

Collecting

• Valued for:
  • Clear crystals
  • Association with beryllium minerals

It has no industrial applications.

Similar and Related Minerals

Beryllonite may be confused with:

• Quartz: Harder and lacks perfect cleavage
• Phenakite: Harder and more durable
• Other colorless phosphates

Distinguishing features include:

• Perfect cleavage
• Moderate hardness
• Occurrence in beryllium-rich pegmatites

Identification Notes for Collectors

• Look for colorless, transparent crystals in pegmatites
• Check for perfect cleavage—a key diagnostic feature
• Note association with beryl and phosphate minerals
• Test hardness (5.5–6)
• Use caution when handling due to cleavage sensitivity

Beryllonite is a rare beryllium phosphate mineral, recognized for its clarity and perfect cleavage, and is primarily valued by collectors and as an occasional gemstone despite its fragility.