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 — that is 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.