Ferriallanite-(Ce) is a rare member of the epidote group characterized by high iron content and significant cerium substitution. Collectors typically find it as dark, opaque, prismatic crystals or massive aggregates in alkaline igneous environments. Due to its radioactive nature, it is prized by advanced collectors and should be stored with appropriate precautions.
Is this ferriallanite-(ce)?
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 ferriallanite-(ce) with a known reference. Ferriallanite-(Ce) sits at Mohs 6-6.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ferriallanite-(Ce) leaves a brown streak.
- 3Read the lusterHold the specimen under a strong light. Ferriallanite-(Ce) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, massive, granular.
Often confused with
Ferriallanite-(Ce) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Ferriallanite-(Ce) leaves brown, Allanite leaves gray; luster reads vitreous on Ferriallanite-(Ce) and submetallic on Allanite.
How to tell apart: Streak differs — Ferriallanite-(Ce) leaves brown, Epidote leaves white.
Often found alongside ferriallanite-(ce)
Minerals reported to co-occur with ferriallanite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- {CaCe}{Fe³⁺Fe²⁺}AlFe³⁺(Si₂O₇)(SiO₄)O(OH)
- Mohs hardness
- 6-6.5
- Density
- 4.1-4.2 g/cm³
- Streak
- Brown
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Massive, Granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks, Pegmatites
- Typical price
- $20-150 thumbnail
Where rockhounds find ferriallanite-(ce)
Classic worldwide localities
- Kola Peninsula, Russia
- Sweden
- Norway
- Japan
Field-hunting tip
Look in alkaline igneous rocks, pegmatites country — that is the host setting where ferriallanite-(ce) typically forms. If you start seeing feldspar, quartz, biotite 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 ferriallanite-(ce)?+
Where is ferriallanite-(ce) found?+
How much is ferriallanite-(ce) worth?+
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What rocks look like ferriallanite-(ce)?+
What minerals are found with ferriallanite-(ce)?+
What kind of rock does ferriallanite-(ce) form in?+
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Find ferriallanite-(ce) on the map
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