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, so Gonyerite leaves yellowish, Clinochlore leaves white.

How to tell apart: Streak differs, so 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, 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.