Ferrihollandite is a rare member of the hollandite group, appearing as a dark, metallic oxide. It typically forms in metamorphic manganese-rich environments, often occurring as fibrous or acicular aggregates that can be visually indistinguishable from other manganese oxides without analytical testing.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareHollandite Group family

Ferrihollandite

Hardness: 6
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this ferrihollandite?

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 ferrihollandite with a known reference. Ferrihollandite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: black.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: black, gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: fibrous, acicular, massive.

Often confused with

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

How to tell apart: Streak differs, so Ferrihollandite leaves black, Cryptomelane leaves brownish black.

Often found alongside ferrihollandite

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

All properties

Chemical formula: Ba(Mn₆Fe₂)O₁₆
Mohs hardness: 6
Density: 4.7-5.0 g/cm³
Colors: Black Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Fibrous, acicular, massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: metamorphic manganese deposits

Where rockhounds find ferrihollandite

Classic worldwide localities

Sweden
India
Germany
USA

Field-hunting tip

Where it forms: metamorphic manganese deposits. If you start seeing hausmannite, braunite, baryte in float, you are in the right ground. Typical habit: fibrous, acicular, massive. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ferrihollandite?+

Mohs hardness is 6. Luster: metallic. The streak is black. Common colors include black, gray.

Where is ferrihollandite found?+

Notable localities include Sweden; India; Germany; USA.

What rocks look like ferrihollandite?+

Ferrihollandite is most often confused with Hollandite, Cryptomelane, Pyrolusite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ferrihollandite?+

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

What kind of rock does ferrihollandite form in?+

Where it forms: metamorphic manganese deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ferrihollandite used for?+

Ferrihollandite is used in collector.

Find ferrihollandite on the map

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