Tegengrenite is a rare manganese-magnesium oxide belonging to the spinel group. It is primarily found as tiny, metallic, black grains within manganese-rich metamorphic rocks, most notably at the famous Långban locality in Sweden.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareSpinel Group family

Tegengrenite

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

Is this tegengrenite?

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 tegengrenite with a known reference. Tegengrenite 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. Tegengrenite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Tegengrenite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black.
5
Look at form & habit
Crystal system: cubic. Typical habit: anhedral grains.

Often confused with

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

How to tell apart: Streak differs — Tegengrenite leaves black, Hausmannite leaves brownish-red; luster reads metallic on Tegengrenite and submetallic on Hausmannite.

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Often found alongside tegengrenite

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

All properties

Chemical formula: Mg(Mn,Sb)₂O₄
Mohs hardness: 6
Density: 4.67 g/cm³
Colors: Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Metamorphosed Manganese Ore Deposits
Typical price: n/a

Where rockhounds find tegengrenite

Classic worldwide localities

Långban, Sweden

Field-hunting tip

Look in metamorphosed manganese ore deposits country — that is the host setting where tegengrenite typically forms. If you start seeing hausmannite, magnetite, dolomite in float, you are in the right ground. Field specimens usually show a anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tegengrenite?+

Mohs hardness is 6. It typically shows a metallic luster. The streak is black. Common colors include black.

Where is tegengrenite found?+

Notable localities include Långban, Sweden.

How much is tegengrenite worth?+

Typical asking prices fall in the range of n/a. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like tegengrenite?+

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

What minerals are found with tegengrenite?+

Tegengrenite commonly co-occurs with Hausmannite, Magnetite, Dolomite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tegengrenite form in?+

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

What is tegengrenite used for?+

Tegengrenite is used in collector.

Find tegengrenite on the map

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