Ferriperbøeite-(La) is an exceptionally rare member of the perbøeite group, primarily identified through geochemical analysis. It typically occurs as dark, non-transparent grains within skarn environments where lanthanum enrichment has occurred. Collectors prize it as a rare species of the epidote supergroup.
Is this ferriperbøeite-(la)?
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 ferriperbøeite-(la) with a known reference. Ferriperbøeite-(La) sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ferriperbøeite-(La) leaves a brownish streak.
- 3Read the lusterHold the specimen under a strong light. Ferriperbøeite-(La) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral to subhedral grains.
Often confused with
Ferriperbøeite-(La) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Ferriperbøeite-(La) leaves brownish, Perbøeite-(Ce) leaves white.
How to tell apart: Streak differs — Ferriperbøeite-(La) leaves brownish, Allanite leaves gray; luster reads vitreous on Ferriperbøeite-(La) and submetallic on Allanite.
Often found alongside ferriperbøeite-(la)
Minerals reported to co-occur with ferriperbøeite-(la). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaLaFe³⁺AlMgSi₅O₁₇(OH)
- Mohs hardness
- 6-7
- Density
- 4.15 g/cm³
- Streak
- Brownish
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral to Subhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Skarn Deposits
- Typical price
- $100-500 for rare micro-specimens
Where rockhounds find ferriperbøeite-(la)
Classic worldwide localities
- Malmkärra mine, Norberg, Västmanland, Sweden
Field-hunting tip
Look in skarn deposits country — that is the host setting where ferriperbøeite-(la) typically forms. If you start seeing calcite, tremolite, andradite in float, you are in the right ground. Field specimens usually show a anhedral to subhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferriperbøeite-(la)?+
Where is ferriperbøeite-(la) found?+
How much is ferriperbøeite-(la) worth?+
What rocks look like ferriperbøeite-(la)?+
What minerals are found with ferriperbøeite-(la)?+
What kind of rock does ferriperbøeite-(la) form in?+
What is ferriperbøeite-(la) used for?+
Find ferriperbøeite-(la) on the map
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