Gonyerite is an extremely rare member of the chlorite group, typically found as platy, micaceous crystals in manganese-rich metamorphic environments. It is most famous for its occurrences in the Långban mines of Sweden and is highly sought after by collectors of manganese minerals.

Hardness

2-3

Mohs

Luster

Pearly

Streak

Yellowish

Transparency

Translucent

mineralrareChlorite Group family

Gonyerite

Hardness: 2-3
Luster: Pearly
Streak: Yellowish
Transparency: Translucent

Is this gonyerite?

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 gonyerite with a known reference. Gonyerite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Gonyerite leaves a yellowish streak.
3
Read the luster
Hold the specimen under a strong light. Gonyerite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-brown, brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy aggregates, micaceous.

Often confused with

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

mineral

Clinochlore

Mohs 2-2.5

How to tell apart: Streak differs — Gonyerite leaves yellowish, Clinochlore leaves white.

How to tell apart: Streak differs — Gonyerite leaves yellowish, Chamosite leaves white to pale green.

Compare →

Often found alongside gonyerite

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

All properties

Chemical formula: (Mn,Mg,Fe)₅Fe(Si,Fe)₄O₁₀(OH)₈
Mohs hardness: 2-3
Density: 3.37 g/cm³
Colors: Yellow Yellowish-brown Brown
Streak: Yellowish
Luster: Pearly
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Platy Aggregates, Micaceous
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Metamorphic Manganese Ore Deposits
Typical price: $50-300 per specimen

Where rockhounds find gonyerite

Classic worldwide localities

Långban, Sweden

Field-hunting tip

Look in metamorphic manganese ore deposits country — that is the host setting where gonyerite typically forms. If you start seeing hausmannite, braunite, baryte in float, you are in the right ground. Field specimens usually show a platy aggregates, micaceous habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gonyerite?+

Mohs hardness is 2-3. It typically shows a pearly luster. The streak is yellowish. Common colors include yellow, yellowish-brown, brown.

Where is gonyerite found?+

Notable localities include Långban, Sweden.

How much is gonyerite 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 gonyerite?+

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

What minerals are found with gonyerite?+

Gonyerite commonly co-occurs with Hausmannite, Braunite, Baryte. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gonyerite form in?+

Gonyerite typically forms in metamorphic manganese ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gonyerite used for?+

Gonyerite is used in collector.

Find gonyerite on the map

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