Ferro-ferri-obertiite is a rare member of the amphibole supergroup characterized by high iron and sodium content. It typically occurs as small prismatic crystals within alkaline igneous environments and is primarily sought after by advanced mineral collectors and researchers.
Is this ferro-ferri-obertiite?
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 ferro-ferri-obertiite with a known reference. Ferro-ferri-obertiite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark green, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, granular.
Often confused with
Ferro-ferri-obertiite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ferro-ferri-obertiite leaves pale green, Arfvedsonite leaves deep bluish gray, gray-green.
How to tell apart: Streak differs, so Ferro-ferri-obertiite leaves pale green, Riebeckite leaves greenish brown.
Often found alongside ferro-ferri-obertiite
Minerals reported to co-occur with ferro-ferri-obertiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaNa₂(Fe₃FeTi)Si₈O₂₂O₂
- Mohs hardness
- 5-6
- Density
- 3.3-3.4 g/cm³
- Colors
- Streak
- Pale green
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, granular
- Cleavage
- Perfect prismatic
- Rarity
- Rare
- Uses
- Collector
- Host rock
- alkaline igneous rocks
Where rockhounds find ferro-ferri-obertiite
Classic worldwide localities
- Italy
- Canada
Field-hunting tip
Where it forms: alkaline igneous rocks. If you start seeing quartz, albite, aegirine in float, you are in the right ground. Typical habit: prismatic, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferro-ferri-obertiite?+
Where is ferro-ferri-obertiite found?+
What rocks look like ferro-ferri-obertiite?+
What minerals are found with ferro-ferri-obertiite?+
What kind of rock does ferro-ferri-obertiite form in?+
What is ferro-ferri-obertiite used for?+
Find ferro-ferri-obertiite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
