Ferriakasakaite-(Ce) is a rare member of the epidote supergroup found primarily in metamorphosed manganese-rich rocks. Collectors will typically identify this species through professional X-ray diffraction or chemical analysis due to its visual similarity to dark, massive members of the allanite subgroup.
Is this ferriakasakaite-(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 ferriakasakaite-(ce) with a known reference. Ferriakasakaite-(Ce) sits at Mohs 5.5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral to subhedral grains.
Often confused with
Ferriakasakaite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ferriakasakaite-(Ce) leaves brown, Epidote leaves grayish white.
How to tell apart: Streak differs, so Ferriakasakaite-(Ce) leaves brown, Allanite leaves gray; luster reads vitreous on Ferriakasakaite-(Ce) and submetallic on Allanite.
Often found alongside ferriakasakaite-(ce)
Minerals reported to co-occur with ferriakasakaite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaCeFe³⁺AlMn²⁺(Si₂O₇)(SiO₄)O(OH)
- Mohs hardness
- 5.5-6
- Density
- 4.02 g/cm³
- Colors
- Streak
- Brown
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral to subhedral grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a manganese deposit in metasedimentary rocks
Where rockhounds find ferriakasakaite-(ce)
Classic worldwide localities
- Monte Maniglia, Bellino, Varaita Valley, Cuneo Province, Piedmont, Italy
Field-hunting tip
Where it forms: In a manganese deposit in metasedimentary rocks. If you start seeing calcite, hematite, manganiandrosite- in float, you are in the right ground. Typical habit: anhedral to subhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferriakasakaite-(ce)?+
Where is ferriakasakaite-(ce) found?+
What rocks look like ferriakasakaite-(ce)?+
What minerals are found with ferriakasakaite-(ce)?+
What kind of rock does ferriakasakaite-(ce) form in?+
What is ferriakasakaite-(ce) used for?+
Find ferriakasakaite-(ce) on the map
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