Ganterite is a rare barium-rich mica typically found in high-grade metamorphic rocks. It forms thin, platy, micaceous crystals that are visually indistinguishable from muscovite without analytical testing.

Hardness

2.5

Mohs

Luster

Pearly

Streak

White

Transparency

Transparent

mineralrareMica Group family

Ganterite

Hardness: 2.5
Luster: Pearly
Streak: White
Transparency: Transparent

No image

Is this ganterite?

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 ganterite with a known reference. Ganterite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Ganterite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Ganterite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: white, colorless, gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals.

Often confused with

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

Often found alongside ganterite

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

All properties

Chemical formula: (Ba,K)Al₂(Al,Si)₄O₁₀(OH)₂
Mohs hardness: 2.5
Density: 2.95 g/cm³
Colors: White Colorless Gray
Streak: White
Luster: Pearly
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Platy Crystals
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Metamorphic Pelitic Schists
Typical price: $50-300 per specimen

Where rockhounds find ganterite

Classic worldwide localities

Ganter Valley, Switzerland
Valle Antigorio, Italy

Field-hunting tip

Look in metamorphic pelitic schists country — that is the host setting where ganterite typically forms. If you start seeing quartz, kyanite, staurolite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ganterite?+

Mohs hardness is 2.5. It typically shows a pearly luster. The streak is white. Common colors include white, colorless, gray.

Where is ganterite found?+

Notable localities include Ganter Valley, Switzerland; Valle Antigorio, Italy.

How much is ganterite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like ganterite?+

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

What minerals are found with ganterite?+

Ganterite commonly co-occurs with Quartz, Kyanite, Staurolite, Garnet. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ganterite form in?+

Ganterite typically forms in metamorphic pelitic schists. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ganterite used for?+

Ganterite is used in collector.

Find ganterite on the map

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