Norrishite is an extremely rare trioctahedral mica found primarily in the manganese mines of the Kalahari Manganese Field. It typically occurs as small, reddish-brown platy crystals associated with various other manganese minerals in high-grade metamorphic environments.

Hardness

2.5-3

Mohs

Luster

Pearly

Streak

White

Transparency

Translucent

mineralrareMica Group family

Norrishite

Hardness: 2.5-3
Luster: Pearly
Streak: White
Transparency: Translucent

Is this norrishite?

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 norrishite with a known reference. Norrishite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Norrishite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Norrishite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: red, brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals.

Often confused with

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

Often found alongside norrishite

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

All properties

Chemical formula: KLiMn₂Si₄O₁₀O₂
Mohs hardness: 2.5-3
Density: 3.32 g/cm³
Colors: Red Brown
Streak: White
Luster: Pearly
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Platy Crystals
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Manganese Deposits
Typical price: $50-300 per specimen

Where rockhounds find norrishite

Classic worldwide localities

Wessels Mine, South Africa

Field-hunting tip

Look in hydrothermal veins in manganese deposits country, the host setting where norrishite typically forms. If you start seeing bultfonteinite, hausmannite, calcite 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 norrishite?+

Mohs hardness is 2.5-3. It typically shows a pearly luster. The streak is white. Common colors include red, brown.

Where is norrishite found?+

Notable localities include Wessels Mine, South Africa.

How much is norrishite 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 norrishite?+

Norrishite 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 norrishite?+

Norrishite commonly co-occurs with Bultfonteinite, Hausmannite, Calcite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does norrishite form in?+

Norrishite typically forms in hydrothermal veins in manganese deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is norrishite used for?+

Norrishite is used in collector.

Find norrishite on the map

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