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Jeffreyite is a rare beryllium-bearing mineral first identified at the famous Jeffrey Mine in Quebec. It typically forms as delicate, acicular, or prismatic crystals and is prized for its notable fluorescence under ultraviolet light.

Hardness
~5
Mohs
Luster
Vitreous
Streak
White
Transparency
Transparent

Is this jeffreyite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

  • 1
    Test the hardness
    Try to scratch jeffreyite with a known reference. Jeffreyite sits at Mohs ~5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: white.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: vitreous.
  • 4
    Match the color range
    Compare against the expected color range: colorless.
  • 5
    Look at form & habit
    Crystal system: orthorhombic. Typical habit: prismatic crystals, acicular.

Often confused with

Jeffreyite vs. its common look-alikes, and how to tell them apart in the field.

Leucophanite mineral
mineral
Leucophanite
Mohs 3.5-4

How to tell apart: Jeffreyite is noticeably harder (Mohs ~5 vs. 3.5-4).

Compare →

Often found alongside jeffreyite

Minerals reported to co-occur with jeffreyite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula
(Ca,Na)₂(Be,Al)Si₂(O,OH)₇
Mohs hardness
~5
Density
2.99 g/cm³
Colors
Colorless
Streak
White
Luster
Vitreous
Transparency
Transparent
Crystal system
Orthorhombic
Crystal habit
Prismatic crystals, acicular
Cleavage
Perfect on {001} and {110}
Fluorescence
Bright white/yellow under SW UV
Rarity
Rare
Uses
Collector, Scientific research
Host rock
In a cavity in a highly calcium-metasomatized granite dike

Where rockhounds find jeffreyite

Classic worldwide localities

  • Jeffrey mine, Asbestos, Quebec, Canada

Field-hunting tip

Where it forms: In a cavity in a highly calcium-metasomatized granite dike. If you start seeing grossular in float, you are in the right ground. Typical habit: prismatic crystals, acicular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify jeffreyite?+
Mohs hardness is ~5. Luster: vitreous. The streak is white. Common colors include colorless.
Where is jeffreyite found?+
Notable localities include Jeffrey mine, Asbestos, Quebec, Canada.
Is jeffreyite safe to handle?+
Jeffreyite contains beryllium. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.
What rocks look like jeffreyite?+
Jeffreyite is most often confused with Leucophanite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with jeffreyite?+
Jeffreyite commonly co-occurs with Grossular. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does jeffreyite form in?+
Where it forms: In a cavity in a highly calcium-metasomatized granite dike. Working float back to the host body is the standard way to chase a fresh occurrence.
What is jeffreyite used for?+
Jeffreyite is used in collector, scientific research.

Find jeffreyite on the map

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