Ferriakasakaite-(La) is an extremely rare member of the epidote supergroup characterized by its high lanthanum content. It typically occurs as small, dark anhedral grains embedded within metamorphic rocks in specialized geological environments. Collectors primarily seek this mineral for its significance in rare-earth element mineralogy.
Is this ferriakasakaite-(la)?
4-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-(la) with a known reference. Ferriakasakaite-(La) sits at Mohs 6-7, softer than the next harder reference, harder than the previous one.
- 2Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 3Match the color rangeCompare against the expected color range: dark brown.
- 4Look at form & habitCrystal system: monoclinic. Typical habit: anhedral grains.
Often confused with
Ferriakasakaite-(La) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside ferriakasakaite-(la)
Minerals reported to co-occur with ferriakasakaite-(la). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaLaFe³⁺AlMn²⁺(Si₂O₇)(SiO₄)O(OH)
- Mohs hardness
- 6-7
- Density
- 4.22 g/cm³
- Colors
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral grains
- Cleavage
- Imperfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In tephroite-calcite veinlets cutting a stratiform ferromanganese deposit
Where rockhounds find ferriakasakaite-(la)
Classic worldwide localities
- Shobu area, Ise City, Mie Prefecture, Japan
Field-hunting tip
Where it forms: In tephroite-calcite veinlets cutting a stratiform ferromanganese deposit. If you start seeing ferriandrosite-, rhodochrosite, bementite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferriakasakaite-(la)?+
Where is ferriakasakaite-(la) found?+
What rocks look like ferriakasakaite-(la)?+
What minerals are found with ferriakasakaite-(la)?+
What kind of rock does ferriakasakaite-(la) form in?+
What is ferriakasakaite-(la) used for?+
Find ferriakasakaite-(la) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
