Ferri-taramite is a rare member of the amphibole supergroup typically found in alkaline igneous environments. It presents as dark, prismatic to massive aggregates and is primarily valued as a rare species by mineral collectors. It is visually indistinguishable from many other dark amphiboles without advanced chemical analysis like electron microprobe.
Is this ferri-taramite?
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-taramite with a known reference. Ferri-taramite 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-taramite leaves a greyish white streak.
- 3Read the lusterHold the specimen under a strong light. Ferri-taramite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, dark green, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, massive, fibrous.
Often confused with
Ferri-taramite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Ferri-taramite leaves greyish white, Arfvedsonite leaves grey to bluish-grey.
How to tell apart: Streak differs — Ferri-taramite leaves greyish white, Taramite leaves white.
How to tell apart: Streak differs — Ferri-taramite leaves greyish white, Hornblende leaves grayish-white.
Often found alongside ferri-taramite
Minerals reported to co-occur with ferri-taramite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na(NaCa)(Fe²⁺₃Fe³⁺₂)(Si₆Al₂)O₂₂(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.3-3.5 g/cm³
- Colors
- Streak
- Greyish White
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Massive, Fibrous
- Cleavage
- Perfect {110}
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Alkaline Igneous Rocks
- Typical price
- $20-150 per specimen
Where rockhounds find ferri-taramite
Classic worldwide localities
- Khibiny Massif, Russia
- Skaergaard Intrusion, Greenland
- Magnet Cove, USA
Field-hunting tip
Look in alkaline igneous rocks country — that is the host setting where ferri-taramite typically forms. If you start seeing nepheline, aegirine, titanite in float, you are in the right ground. Field specimens usually show a prismatic crystals, massive, fibrous habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ferri-taramite on the map
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