Kvanefjeldite is a rare phyllosilicate mineral found primarily in the unique agpaitic rocks of the Ilimaussaq complex in Greenland. It is highly valued by collectors for its brilliant white fluorescence under short-wave ultraviolet light and its tight association with other exotic alkaline minerals.

Hardness

5.5-6

Mohs

Luster

Vitreous, pearly on {010} cleavage

Streak

White

Transparency

Transparent

mineralrare

Kvanefjeldite

Hardness: 5.5-6
Luster: Vitreous, pearly on {010} cleavage
Streak: White
Transparency: Transparent

Is this kvanefjeldite?

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 kvanefjeldite with a known reference. Kvanefjeldite sits at Mohs 5.5-6, 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, pearly on {010} cleavage.
4
Match the color range
Compare against the expected color range: violet pink.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, massive, granular.

Often confused with

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

How to tell apart: Streak differs, so Kvanefjeldite leaves white, Steenstrupine-(Ce) leaves brownish, nearly white; luster reads vitreous, pearly on {010} cleavage on Kvanefjeldite and dull on Steenstrupine-(Ce).

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Often found alongside kvanefjeldite

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

All properties

Chemical formula: Na₄CaSi₆O₁₄(OH)₂
Mohs hardness: 5.5-6
Density: 2.55 g/cm³
Colors: Violet pink
Streak: White
Luster: Vitreous, pearly on {010} cleavage
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals, massive, granular
Cleavage: Good on {010}; poor on {101}, intersecting at 83°
Fluorescence: Bright white under SW UV
Rarity: Rare
Uses: Collector
Host rock: As patches, streaks, and veinlets cutting arfvedsonite-bearing nepheline syenite; probably of late-stage hydrothermal origin

Where rockhounds find kvanefjeldite

Classic worldwide localities

On the Kvanefjeld Plateau, in the Ilimaussaq intrusion, southern Greenland (type locality)

Field-hunting tip

Where it forms: As patches, streaks, and veinlets cutting arfvedsonite-bearing nepheline syenite; probably of late-stage hydrothermal origin. If you start seeing villiaumite, analcime in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kvanefjeldite?+

Mohs hardness is 5.5-6. Luster: vitreous, pearly on {010} cleavage. The streak is white. Common colors include violet pink.

Where is kvanefjeldite found?+

Notable localities include On the Kvanefjeld Plateau, in the Ilimaussaq intrusion, southern Greenland (type locality).

Is kvanefjeldite safe to handle?+

Kvanefjeldite contains radioactive elements (often associated with eudialyte and steenstrupine) and should be stored in a labeled, lead-lined, or sealed container to minimize exposure. Wash hands thoroughly after handling.

What rocks look like kvanefjeldite?+

Kvanefjeldite is most often confused with Eudialyte, Steenstrupine-(Ce). A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kvanefjeldite?+

Kvanefjeldite commonly co-occurs with Villiaumite, Analcime. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kvanefjeldite form in?+

Where it forms: As patches, streaks, and veinlets cutting arfvedsonite-bearing nepheline syenite; probably of late-stage hydrothermal origin. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kvanefjeldite used for?+

Kvanefjeldite is used in collector.

Find kvanefjeldite on the map

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