Katophorite is a rare member of the sodic-calcic amphibole group typically found in alkaline igneous environments. It is identified by its dark, elongated prismatic crystals and distinct pleochroism, which can be challenging to distinguish from other dark amphiboles without chemical analysis.

Hardness

5-6

Mohs

Luster

Vitreous

Streak

Brown

Transparency

Opaque

mineralrareAmphibole Supergroup family

Katophorite

Hardness: 5-6
Luster: Vitreous
Streak: Brown
Transparency: Opaque

Is this katophorite?

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 katophorite with a known reference. Katophorite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Katophorite leaves a brown streak.
3
Read the luster
Hold the specimen under a strong light. Katophorite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: dark brown, brownish red, black.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals.

Often confused with

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

mineral

Hornblende

Mohs 5-6

How to tell apart: Streak differs — Katophorite leaves brown, Hornblende leaves grayish-white.

How to tell apart: Streak differs — Katophorite leaves brown, Arfvedsonite leaves grey to bluish-grey.

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Often found alongside katophorite

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

All properties

Chemical formula: Na(NaCa)(Mg₄Ti)Si₇AlO₂₂(OH)₂
Mohs hardness: 5-6
Density: 3.35-3.50 g/cm³
Colors: Dark Brown Brownish Red Black
Streak: Brown
Luster: Vitreous
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals
Cleavage: Perfect in Two Directions
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Alkaline Igneous Rocks
Typical price: $20-100 per specimen

Where rockhounds find katophorite

Classic worldwide localities

Norway
Sweden
Canada
USA

Field-hunting tip

Look in alkaline igneous rocks country — that is the host setting where katophorite typically forms. If you start seeing nepheline, aegirine, albite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify katophorite?+

Mohs hardness is 5-6. It typically shows a vitreous luster. The streak is brown. Common colors include dark brown, brownish red, black.

Where is katophorite found?+

Notable localities include Norway; Sweden; Canada; USA.

How much is katophorite worth?+

Typical asking prices fall in the range of $20-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like katophorite?+

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

What minerals are found with katophorite?+

Katophorite commonly co-occurs with Nepheline, Aegirine, Albite, Titanite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does katophorite form in?+

Katophorite typically forms in alkaline igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is katophorite used for?+

Katophorite is used in collector, scientific research.

Find katophorite on the map

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