Nabesite is a very rare sodium beryllium silicate mineral found primarily within the hyper-alkaline rocks of the Ilímaussaq complex. It typically occurs as small, transparent tabular crystals that can be difficult to distinguish from other beryllium-bearing zeolites without chemical analysis.

Hardness

5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareZeolite Group family

Nabesite

Hardness: 5-6
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this nabesite?

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 nabesite with a known reference. Nabesite sits at Mohs 5-6, 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, white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: platy, thin.

Often confused with

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

mineral

Leucophanite

Mohs 3.5-4

How to tell apart: Nabesite is noticeably harder (Mohs 5-6 vs. 3.5-4).

How to tell apart: Luster reads vitreous on Nabesite and pearly on cleavages, vitreous on fractures on Epididymite.

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Often found alongside nabesite

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

All properties

Chemical formula: Na₂BeSi₄O₁₀·4H₂O
Mohs hardness: 5-6
Density: 2.16 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Platy, thin
Cleavage: Good on {110} and {001}
Rarity: Rare
Uses: Collector
Host rock: In albite-lined cavities within tugtupite-bearing albitites

Where rockhounds find nabesite

Classic worldwide localities

Kvanefjeld Plateau, northwestern extremity of the Ilímaussaq complex, South Greenland

Field-hunting tip

Where it forms: In albite-lined cavities within tugtupite-bearing albitites. If you start seeing gmelinite, neptunite, analcime in float, you are in the right ground. Typical habit: platy, thin. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify nabesite?+

Mohs hardness is 5-6. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is nabesite found?+

Notable localities include Kvanefjeld Plateau, northwestern extremity of the Ilímaussaq complex, South Greenland.

Is nabesite safe to handle?+

Nabesite 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 nabesite?+

Nabesite is most often confused with Leucophanite, Epididymite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with nabesite?+

Nabesite commonly co-occurs with Gmelinite, Neptunite, Analcime, Gonnardite, Lovdarite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does nabesite form in?+

Where it forms: In albite-lined cavities within tugtupite-bearing albitites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is nabesite used for?+

Nabesite is used in collector.

Find nabesite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.