Ferri-katophorite is a rare member of the calcic-sodic amphibole group, typically found in alkaline igneous environments. It presents as dark, prismatic to massive aggregates and is primarily sought after by advanced mineral collectors interested in complex silicate geochemistry.
Is this ferri-katophorite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch ferri-katophorite with a known reference. Ferri-katophorite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ferri-katophorite leaves a pale gray streak.
- 3Read the lusterHold the specimen under a strong light. Ferri-katophorite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark green, black, brownish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, massive, granular.
Often confused with
Ferri-katophorite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Ferri-katophorite leaves pale gray, Hornblende leaves grayish-white.
How to tell apart: Streak differs — Ferri-katophorite leaves pale gray, Arfvedsonite leaves grey to bluish-grey.
How to tell apart: Streak differs — Ferri-katophorite leaves pale gray, Katophorite leaves brown.
Often found alongside ferri-katophorite
Minerals reported to co-occur with ferri-katophorite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na(NaCa)(Fe²⁺₄Fe³⁺)Si₇AlO₂₂(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.3-3.5 g/cm³
- Streak
- Pale Gray
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Massive, Granular
- Cleavage
- Perfect On {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks, Syenites, Carbonatites
- Typical price
- $20-100 per specimen
Where rockhounds find ferri-katophorite
Classic worldwide localities
- Norway
- Canada
- USA
- Russia
Field-hunting tip
Look in alkaline igneous rocks, syenites, carbonatites country — that is the host setting where ferri-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, massive, granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferri-katophorite?+
Where is ferri-katophorite found?+
How much is ferri-katophorite worth?+
What rocks look like ferri-katophorite?+
What minerals are found with ferri-katophorite?+
What kind of rock does ferri-katophorite form in?+
What is ferri-katophorite used for?+
Find ferri-katophorite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
