Ferri-mottanaite-(Ce) is a rare boron-bearing sorosilicate mineral belonging to the allanite group. It is primarily found in metamorphic environments and is identified by its distinct chemical composition featuring iron and cerium, usually occurring as small, brownish, prismatic crystals.
Is this ferri-mottanaite-(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 ferri-mottanaite-(ce) with a known reference. Ferri-mottanaite-(Ce) sits at Mohs 6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: very pale-yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellow, brown, reddish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Ferri-mottanaite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ferri-mottanaite-(Ce) leaves very pale-yellow, Allanite leaves gray; luster reads vitreous on Ferri-mottanaite-(Ce) and submetallic on Allanite.
How to tell apart: Streak differs, so Ferri-mottanaite-(Ce) leaves very pale-yellow, Mottanaite-(Ce) leaves white.
How to tell apart: Streak differs, so Ferri-mottanaite-(Ce) leaves very pale-yellow, Epidote leaves grayish white.
Often found alongside ferri-mottanaite-(ce)
Minerals reported to co-occur with ferri-mottanaite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Ce₂Fe(Be₁.₅□₀.₅)[Si₄B₄O₂₂]O₂
- Mohs hardness
- 6
- Density
- 3.952 g/cm³
- Colors
- Streak
- Very pale-yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In miarolitic cavities in feldspathoid-bearing alkali-syenitic pyroclastic ejecta
Where rockhounds find ferri-mottanaite-(ce)
Classic worldwide localities
- Tre Croci, near Vetralla, Vico volcanic province, Italy
Field-hunting tip
Where it forms: In miarolitic cavities in feldspathoid-bearing alkali-syenitic pyroclastic ejecta. If you start seeing fluorite, sanidine, cancrinite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferri-mottanaite-(ce)?+
Where is ferri-mottanaite-(ce) found?+
Is ferri-mottanaite-(ce) safe to handle?+
What rocks look like ferri-mottanaite-(ce)?+
What minerals are found with ferri-mottanaite-(ce)?+
What kind of rock does ferri-mottanaite-(ce) form in?+
What is ferri-mottanaite-(ce) used for?+
Find ferri-mottanaite-(ce) on the map
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