Ferri-obertiite is a rare member of the amphibole supergroup, typically found in highly alkaline igneous environments. It usually appears as small, dark-colored prismatic crystals that are difficult to distinguish from other amphiboles without specialized chemical analysis like electron microprobe testing.
Is this ferri-obertiite?
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 ferri-obertiite with a known reference. Ferri-obertiite sits at Mohs 5-6, 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: pink-orange.
- 4Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Ferri-obertiite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside ferri-obertiite
Minerals reported to co-occur with ferri-obertiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na(Na₂)(Mg₃Fe³⁺Ti)Si₈O₂₂O₂
- Mohs hardness
- 5-6
- Density
- 3.145 g/cm³
- Colors
- Pink-orange
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals
- Cleavage
- Perfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From vesicles in silicate veins within basaltic scoria
Where rockhounds find ferri-obertiite
Classic worldwide localities
- Rothenberg Volcano, Eifel complex, Rhineland-Palatinate, Germany
Field-hunting tip
Where it forms: From vesicles in silicate veins within basaltic scoria. If you start seeing sanidine, eifelite, tridymite 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-obertiite?+
Where is ferri-obertiite found?+
What rocks look like ferri-obertiite?+
What minerals are found with ferri-obertiite?+
What kind of rock does ferri-obertiite form in?+
What is ferri-obertiite used for?+
Find ferri-obertiite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
