Emmerichite is a very rare member of the mica group found primarily in volcanic ejecta of the Eifel region in Germany. It typically presents as small, yellow to brown platy crystals that are difficult to distinguish from other mica species without sophisticated mineralogical analysis.

Hardness

2.5

Mohs

Luster

Pearly

Streak

White

Transparency

Translucent

mineralrareMica Group family

Emmerichite

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

Is this emmerichite?

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 emmerichite with a known reference. Emmerichite 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. Emmerichite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Emmerichite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals.

Often confused with

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

Often found alongside emmerichite

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

All properties

Chemical formula: Na(Fe³⁺,Mg)₂(Fe³⁺,Al,Ti,Mg)(Si,Al)₄O₁₀(F,O)₂
Mohs hardness: 2.5
Density: 3.1-3.2 g/cm³
Colors: Yellow Brown
Streak: White
Luster: Pearly
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Platy Crystals
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Volcanic Rocks
Typical price: $50-300 for rare micro-specimens

Where rockhounds find emmerichite

Classic worldwide localities

Germany

Field-hunting tip

Look in volcanic rocks country — that is the host setting where emmerichite typically forms. If you start seeing sanidine, augite, magnetite 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 emmerichite?+

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

Where is emmerichite found?+

Notable localities include Germany.

How much is emmerichite worth?+

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

What rocks look like emmerichite?+

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

What minerals are found with emmerichite?+

Emmerichite commonly co-occurs with Sanidine, Augite, Magnetite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does emmerichite form in?+

Emmerichite typically forms in volcanic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is emmerichite used for?+

Emmerichite is used in collector.

Find emmerichite on the map

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