Grischunite is a rare phosphate mineral originally discovered in the manganese deposits of the Falotta mine in Switzerland. It typically appears as reddish-brown massive or granular masses, making it a challenging mineral for field identification without specialized analytical methods.

Hardness

Mohs

Luster

Vitreous

Streak

Yellow-brown to orange

Transparency

Semitransparent

mineralrareGrischunite-Fillowite Group family

Grischunite

Hardness: ~5
Luster: Vitreous
Streak: Yellow-brown to orange
Transparency: Semitransparent

Is this grischunite?

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 grischunite with a known reference. Grischunite 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: yellow-brown to orange.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: dark reddish brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: granular aggregates, rarely as small tabular crystals.

Often confused with

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

mineral

Fillowite

Mohs 4.5

How to tell apart: Streak differs, so Grischunite leaves yellow-brown to orange, Fillowite leaves white; luster reads vitreous on Grischunite and subresinous to greasy on Fillowite.

Compare →

Often found alongside grischunite

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

All properties

Chemical formula: NaCa₂Mn₅Fe(AsO₄)₆·2H₂O
Mohs hardness: ~5
Density: 3.8 g/cm³
Colors: Dark reddish brown
Streak: Yellow-brown to orange
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Orthorhombic
Crystal habit: Granular aggregates, rarely as small tabular crystals
Cleavage: On {010}, perfect
Rarity: Rare
Uses: Collector
Host rock: An alteration product of sarkinite in a manganese deposit

Where rockhounds find grischunite

Classic worldwide localities

Falotta mine, Oberhalbstein, Graubünden, Switzerland

Field-hunting tip

Where it forms: An alteration product of sarkinite in a manganese deposit. If you start seeing sarkinite, brandtite, manganoan berzeliite in float, you are in the right ground. Typical habit: granular aggregates, rarely as small tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify grischunite?+

Mohs hardness is ~5. Luster: vitreous. The streak is yellow-brown to orange. Common colors include dark reddish brown.

Where is grischunite found?+

Notable localities include Falotta mine, Oberhalbstein, Graubünden, Switzerland.

Is grischunite safe to handle?+

Grischunite contains arsenic and calls for real care. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like grischunite?+

Grischunite is most often confused with Fillowite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with grischunite?+

Grischunite commonly co-occurs with Sarkinite, Brandtite, Manganoan berzeliite, Tilasite, Rhodochrosite, Braunite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does grischunite form in?+

Where it forms: An alteration product of sarkinite in a manganese deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is grischunite used for?+

Grischunite is used in collector.

Find grischunite on the map

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